Re: Re: What do you think about a C# 6 like nameof() expression for
FWIW a start to ```nameofall``` using ```RegExp```
https://gist.github.com/guest271314/daa1c6455ec8a2b6b89aff245e95c615
```const nameofall =
/((const|let)\s+)\w+(?=\s+(=|in|of))|class\s+\w+(?=\s)/gi;```
TODO: handle destructuring assignment, default values, shorthand
assignments, e.g.,
```
const [{
a = 1,
b = 2
}, cd] = [...[source]];
```
Usage: ```sourceCode.match(nameofall); // ["const x", "let z", "class G"]```
On Fri, Jun 14, 2019 at 1:05 PM Stas Berkov wrote:
> Can we revisit this issue?
>
>
> In C# there is `nameof`, in Swift you can do the same by calling
>
> ```
>
> let keyPath = \Person.mother.firstName
>
> NSPredicate(format: "%K == %@", keyPath, "Andrew")
>
> ```
>
> Let's introduce `nameof` in ES, please.
>
>
> Devs from TypeScript don't want to introduce this feature in TypeScript
> unless it is available in ES (
> https://github.com/microsoft/TypeScript/issues/1579 )
>
> This feature is eagarly being asked by TypeScript community.
>
>
> I understand there are couple issues related to `nameof` feature in ES.
> They are: minification and what to do if user already has `nameof` function.
>
>
> Minification.
>
> 1. If your code to be minimized be prepared that variable names will also
> change.
>
> 2. (just a possibility) Minimizer can have option to replace
> `nameof(someVar)` with result of `nameof` function.
>
>
>
> What if user already has `nameof` function.
>
> 1. To maintain status quo we can user `nameof` function having priority
> over newly introduced language feature.
>
> 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns
> "userName" string)
> ___
> es-discuss mailing list
> es-discuss@mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
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Re: Re: What do you think about a C# 6 like nameof() expression for
t;
> https://brendaneich.com/2008/04/popularity/) video container that is a
> subset of the Matroska container, where if that method were specified in
> JavaScript a user would be able to do ```mkvmerge({w: true, o:
> "int_all.webm": i: ["int.webm", "int1.webm", "intN.webm"]})``` instead
> of ```$ mkvmerge -w -o int_all.webm int.webm + int1.webm``` at
> ```terminal```.
> >
> >
> >
> >
> > On Mon, Jun 17, 2019 at 11:29 PM Ron Buckton
> wrote:
> >>
> >> > How is VSCode related to JavaScript?
> >>
> >>
> >>
> >> You have ignored the context from Jordan’s email (emphasis added):
> >>
> >>
> >>
> >> >> again, `Object.keys({ y })[0]` will give you the string `y`, and
> will survive refactoring tools. you can even do `function nameof(obj) {
> return Object.keys(obj)[0]; }` and then `nameof({ y })`.
> >>
> >>
> >>
> >> VSCode is a popular editor that supports JavaScript *and* is a
> refactoring tool. Rename refactoring was the subject I was responding to.
> >>
> >>
> >>
> >> There are a number of reasons VSCode has implemented rename refactoring
> in this fashion. Not the least of which is that an editor cannot fully
> understand user intent. Let us say, for example, you are working with Gulp:
> >>
> >>
> >>
> >> ```
> >>
> >> const cwd /*1*/ = ".";
> >>
> >> gulp.src("*.js", { cwd /*2*/ });
> >>
> >> ```
> >>
> >>
> >>
> >> If you were to rename `cwd` at (1) and it *also* renamed the `cwd`
> property at (2), you would have introduced an error in the call because a
> `cwd` option to gulp has a special meaning. Since the editor doesn’t know
> the intent of the user may be to rename *both* symbols, it remains
> conservative and choses only to rename the binding and its references,
> producing:
> >>
> >>
> >>
> >> ```
> >>
> >> const currentDir = ".";
> >>
> >> gulp.src("*.js", { cwd: currentDir });
> >>
> >> ```
> >>
> >>
> >>
> >> There is also the issue of collisions:
> >>
> >>
> >>
> >> ```
> >>
> >> const foo /*1*/ = 1;
> >>
> >> f({ foo /*2*/, bar: 2 });
> >>
> >> ```
> >>
> >>
> >>
> >> If I were to use a refactoring tool to rename `foo` at (1) to `bar`, it
> would *not* be safe to rename the property at (2) as well as it would
> introduce a semantic error that would prevent the entire script from
> executing.
> >>
> >>
> >>
> >> In the context of Jordan’s email, that means that `Object.keys({ y
> })[0]` would *not* necessarily survive refactoring tools.
> >>
> >>
> >>
> >> From: es-discuss On Behalf Of
> guest271314
> >> Sent: Monday, June 17, 2019 7:40 AM
> >> Cc: es-discuss@mozilla.org
> >> Subject: Re: Re: What do you think about a C# 6 like nameof()
> expression for
> >>
> >>
> >>
> >> > In VSCode, if you rename ‘foo’ to ‘bar’ at /1/, you get this:
> >>
> >>
> >>
> >> How is VSCode related to JavaScript?
> >>
> >>
> >>
> >> Is the proposal really based on creating ```nameof``` in JavaScript to
> workaround output at a text editor?
> >>
> >>
> >>
> >> Why not file a bug with the individuals who write the code for VSCode
> or just write a text editor code from scratch which does what you want as
> to "refactoring". Or write the code by hand and test the code to avoid
> having to rely on _any_ text editor to catch your mistakes?
> >>
> >>
> >>
> >>
> >
> > ___
> > es-discuss mailing list
> > es-discuss@mozilla.org
> > https://mail.mozilla.org/listinfo/es-discuss
>
> ___
> es-discuss mailing list
> es-discuss@mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
>
___
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https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
nterpret
> > > what the users' intent is when writing code.
> > >
> > >
> > > In that case ```mkvmerge``` should be specified as a JavaScript method.
> > > ```webm``` is a "popular" (cannot help but to recollect "Popularity"
> > > https://brendaneich.com/2008/04/popularity/) video container that is a
> > > subset of the Matroska container, where if that method were specified in
> > > JavaScript a user would be able to do ```mkvmerge({w: true, o:
> > > "int_all.webm": i: ["int.webm", "int1.webm", "intN.webm"]})```
> > > instead of ```$ mkvmerge -w -o int_all.webm int.webm + int1.webm``` at
> > > ```terminal```.
> > >
> > >
> > >
> > >
> > > On Mon, Jun 17, 2019 at 11:29 PM Ron Buckton > > (mailto:ron.buck...@microsoft.com)> wrote:
> > >>
> > >> > How is VSCode related to JavaScript?
> > >>
> > >>
> > >>
> > >> You have ignored the context from Jordan’s email (emphasis added):
> > >>
> > >>
> > >>
> > >> >> again, `Object.keys({ y })[0]` will give you the string `y`, and will
> > >> >> survive refactoring tools. you can even do `function nameof(obj) {
> > >> >> return Object.keys(obj)[0]; }` and then `nameof({ y })`.
> > >>
> > >>
> > >>
> > >> VSCode is a popular editor that supports JavaScript *and* is a
> > >> refactoring tool. Rename refactoring was the subject I was responding to.
> > >>
> > >>
> > >>
> > >> There are a number of reasons VSCode has implemented rename refactoring
> > >> in this fashion. Not the least of which is that an editor cannot fully
> > >> understand user intent. Let us say, for example, you are working with
> > >> Gulp:
> > >>
> > >>
> > >>
> > >> ```
> > >>
> > >> const cwd /*1*/ = ".";
> > >>
> > >> gulp.src("*.js", { cwd /*2*/ });
> > >>
> > >> ```
> > >>
> > >>
> > >>
> > >> If you were to rename `cwd` at (1) and it *also* renamed the `cwd`
> > >> property at (2), you would have introduced an error in the call because
> > >> a `cwd` option to gulp has a special meaning. Since the editor doesn’t
> > >> know the intent of the user may be to rename *both* symbols, it remains
> > >> conservative and choses only to rename the binding and its references,
> > >> producing:
> > >>
> > >>
> > >>
> > >> ```
> > >>
> > >> const currentDir = ".";
> > >>
> > >> gulp.src("*.js", { cwd: currentDir });
> > >>
> > >> ```
> > >>
> > >>
> > >>
> > >> There is also the issue of collisions:
> > >>
> > >>
> > >>
> > >> ```
> > >>
> > >> const foo /*1*/ = 1;
> > >>
> > >> f({ foo /*2*/, bar: 2 });
> > >>
> > >> ```
> > >>
> > >>
> > >>
> > >> If I were to use a refactoring tool to rename `foo` at (1) to `bar`, it
> > >> would *not* be safe to rename the property at (2) as well as it would
> > >> introduce a semantic error that would prevent the entire script from
> > >> executing.
> > >>
> > >>
> > >>
> > >> In the context of Jordan’s email, that means that `Object.keys({ y
> > >> })[0]` would *not* necessarily survive refactoring tools.
> > >>
> > >>
> > >>
> > >> From: es-discuss > >> (mailto:es-discuss-boun...@mozilla.org)> On Behalf Of guest271314
> > >> Sent: Monday, June 17, 2019 7:40 AM
> > >> Cc: es-discuss@mozilla.org (mailto:es-discuss@mozilla.org)
> > >> Subject: Re: Re: What do you think about a C# 6 like nameof() expression
> > >> for
> > >>
> > >>
> > >>
> > >> > In VSCode, if you rename ‘foo’ to ‘bar’ at /1/, you get this:
> > >>
> > >>
> > >>
> > >> How is VSCode related to JavaScript?
> > >>
> > >>
> > >>
> > >> Is the proposal really based on creating ```nameof``` in JavaScript to
> > >> workaround output at a text editor?
> > >>
> > >>
> > >>
> > >> Why not file a bug with the individuals who write the code for VSCode or
> > >> just write a text editor code from scratch which does what you want as
> > >> to "refactoring". Or write the code by hand and test the code to avoid
> > >> having to rely on _any_ text editor to catch your mistakes?
> > >>
> > >>
> > >>
> > >>
> > >
> > > ___
> > > es-discuss mailing list
> > > es-discuss@mozilla.org (mailto:es-discuss@mozilla.org)
> > > https://mail.mozilla.org/listinfo/es-discuss
>
>
> ___
> es-discuss mailing list
> es-discuss@mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
`Object.keys({ y })[0]` will give you the string `y`, and
> will survive refactoring tools. you can even do `function nameof(obj) {
> return Object.keys(obj)[0]; }` and then `nameof({ y })`.
> >>
> >>
> >>
> >> VSCode is a popular editor that supports JavaScript *and* is a
> refactoring tool. Rename refactoring was the subject I was responding to.
> >>
> >>
> >>
> >> There are a number of reasons VSCode has implemented rename refactoring
> in this fashion. Not the least of which is that an editor cannot fully
> understand user intent. Let us say, for example, you are working with Gulp:
> >>
> >>
> >>
> >> ```
> >>
> >> const cwd /*1*/ = ".";
> >>
> >> gulp.src("*.js", { cwd /*2*/ });
> >>
> >> ```
> >>
> >>
> >>
> >> If you were to rename `cwd` at (1) and it *also* renamed the `cwd`
> property at (2), you would have introduced an error in the call because a
> `cwd` option to gulp has a special meaning. Since the editor doesn’t know
> the intent of the user may be to rename *both* symbols, it remains
> conservative and choses only to rename the binding and its references,
> producing:
> >>
> >>
> >>
> >> ```
> >>
> >> const currentDir = ".";
> >>
> >> gulp.src("*.js", { cwd: currentDir });
> >>
> >> ```
> >>
> >>
> >>
> >> There is also the issue of collisions:
> >>
> >>
> >>
> >> ```
> >>
> >> const foo /*1*/ = 1;
> >>
> >> f({ foo /*2*/, bar: 2 });
> >>
> >> ```
> >>
> >>
> >>
> >> If I were to use a refactoring tool to rename `foo` at (1) to `bar`, it
> would *not* be safe to rename the property at (2) as well as it would
> introduce a semantic error that would prevent the entire script from
> executing.
> >>
> >>
> >>
> >> In the context of Jordan’s email, that means that `Object.keys({ y
> })[0]` would *not* necessarily survive refactoring tools.
> >>
> >>
> >>
> >> From: es-discuss On Behalf Of
> guest271314
> >> Sent: Monday, June 17, 2019 7:40 AM
> >> Cc: es-discuss@mozilla.org
> >> Subject: Re: Re: What do you think about a C# 6 like nameof()
> expression for
> >>
> >>
> >>
> >> > In VSCode, if you rename ‘foo’ to ‘bar’ at /1/, you get this:
> >>
> >>
> >>
> >> How is VSCode related to JavaScript?
> >>
> >>
> >>
> >> Is the proposal really based on creating ```nameof``` in JavaScript to
> workaround output at a text editor?
> >>
> >>
> >>
> >> Why not file a bug with the individuals who write the code for VSCode
> or just write a text editor code from scratch which does what you want as
> to "refactoring". Or write the code by hand and test the code to avoid
> having to rely on _any_ text editor to catch your mistakes?
> >>
> >>
> >>
> >>
> >
> > ___
> > es-discuss mailing list
> > es-discuss@mozilla.org
> > https://mail.mozilla.org/listinfo/es-discuss
>
___
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https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
I get yet again that the forest here is being missed for the trees.
@guest271314 This isn't specific to any one IDE, and isn't even
specific to static tools. As mentioned before, this has applicability
to assertion libraries (like a userland version of Power Assert) as
well as other things. It's almost exclusively just quality-of-life
improvements to developers, but it's not specific to IDEs or even
static tooling.
-
Isiah Meadows
cont...@isiahmeadows.com
www.isiahmeadows.com
On Mon, Jun 17, 2019 at 8:28 PM guest271314 wrote:
>
>
> > You have ignored the context from Jordan’s email (emphasis added):
>
>
>
> >> again, `Object.keys({ y })[0]` will give you the string `y`, and will
> >> survive refactoring tools. you can even do `function nameof(obj) { return
> >> Object.keys(obj)[0]; }` and then `nameof({ y })`.
>
>
> No, did not _ignore_ the context of the email.
>
>
> Simply have no reference point for relying on an external tool, that is,
> essentially a text editor, to write and dynamically "refactor" code. Here,
> the code will be tested outside of the text editor in short order once
> composed.
>
>
> Was able to rename text at Mousepad and record the entire process within 20
> seconds without needing to use ```nameof``` and without encountering any
> issues such as mispelling the variable name or the text editor trying to
> independently determine what the words am typing mean. The text editor is
> just - a text editor.
>
>
> Perhaps other JavaScript users who rely on "refactoring tools" and "rename
> refactoring" in an IDE can relate. Not able to gather the significance of
> ```nameof``` here - as in each case the user has to write the name of the
> variable anyway. To each their own.
>
>
> > VSCode is a popular editor that supports JavaScript *and* is a refactoring
> > tool. Rename refactoring was the subject I was responding to.
>
>
>
>
>
> Was not previously aware or did not realize that the _individual choice_ to
> use a particular text editor was a substantial reason to ask for change to
> the entire JavaScript language in order for specific users to be able to
> interact with an entirely different language.
>
>
> If VSCode is particularly "popular" why cannot VSCode be specified and
> implemented by and for the users who rely on the text editor to interpret
> what the users' intent is when writing code.
>
>
> In that case ```mkvmerge``` should be specified as a JavaScript method.
> ```webm``` is a "popular" (cannot help but to recollect "Popularity"
> https://brendaneich.com/2008/04/popularity/) video container that is a subset
> of the Matroska container, where if that method were specified in JavaScript
> a user would be able to do ```mkvmerge({w: true, o: "int_all.webm": i:
> ["int.webm", "int1.webm", "intN.webm"]})``` instead of ```$ mkvmerge -w
> -o int_all.webm int.webm + int1.webm``` at ```terminal```.
>
>
>
>
> On Mon, Jun 17, 2019 at 11:29 PM Ron Buckton
> wrote:
>>
>> > How is VSCode related to JavaScript?
>>
>>
>>
>> You have ignored the context from Jordan’s email (emphasis added):
>>
>>
>>
>> >> again, `Object.keys({ y })[0]` will give you the string `y`, and will
>> >> survive refactoring tools. you can even do `function nameof(obj) { return
>> >> Object.keys(obj)[0]; }` and then `nameof({ y })`.
>>
>>
>>
>> VSCode is a popular editor that supports JavaScript *and* is a refactoring
>> tool. Rename refactoring was the subject I was responding to.
>>
>>
>>
>> There are a number of reasons VSCode has implemented rename refactoring in
>> this fashion. Not the least of which is that an editor cannot fully
>> understand user intent. Let us say, for example, you are working with Gulp:
>>
>>
>>
>> ```
>>
>> const cwd /*1*/ = ".";
>>
>> gulp.src("*.js", { cwd /*2*/ });
>>
>> ```
>>
>>
>>
>> If you were to rename `cwd` at (1) and it *also* renamed the `cwd` property
>> at (2), you would have introduced an error in the call because a `cwd`
>> option to gulp has a special meaning. Since the editor doesn’t know the
>> intent of the user may be to rename *both* symbols, it remains conservative
>> and choses only to rename the binding and its references, producing:
>>
>>
>>
>> ```
>>
>> const currentDir = ".";
>>
>> gulp.src("*.js", { cwd: currentDir });
>>
>> ```
>>
Re: Re: What do you think about a C# 6 like nameof() expression for
Because the declaration itself is hoisted. The TDZ only delays
*initialization*, not *declaration*.
- For `var`, the declaration is hoisted *and* it's automatically
initialized to `undefined` before executing any body code.
- For `function foo() { ... }`, the declaration is hoisted *and* the
value is automatically initialized to a new function object
encapsulating the function's body before executing any body code.
- For all other types, the declaration is hoisted, but it is *not*
possible to initialize it yet. It's initialized to `undefined` for
`let value;` when that statement is executed, the relevant function
object for `class Foo`, the RHS value for `let value = expr`/`const
value = expr`, and so on. (Most of the complexity is in destructured
bindings and default parameters, but it's not black magic, I promise.)
- Keep in mind it's possible to get a reference to an uninitialized
variable, even though it's not possible to access any value yet.
This mechanism already exists today, and `nameof` would just leverage
that mechanism. The static value would be computed *after* the
variable would have been linked (either at the global scope or after
the declaration exists), and only after falling back to the global
scope would the value fall back to a dynamic lookup and test.
-
Isiah Meadows
cont...@isiahmeadows.com
www.isiahmeadows.com
On Sun, Jun 16, 2019 at 8:15 PM guest271314 wrote:
>
> > - If `y` is directly visible in scope and is neither a parameter or
> destructured binding, `nameof y` should just evaluate to `"y"`. This
> should be agnostic to whether the binding has been declared yet, so in
> your example, `x` should be set to `"y"`.
>
> The 1st question at
> https://esdiscuss.org/topic/what-do-you-think-about-a-c-6-like-nameof-expression-for#content-33
> remains:
>
> Without having composed or previously read the source code, at line 1
> adjacent to ```nameof``` how does the user know that there will be later
> declared variable named ```y```?
>
>
>
> On Sun, Jun 16, 2019 at 7:04 AM Isiah Meadows wrote:
>>
>> Here's my opinion:
>>
>> - If `y` is directly visible in scope and is neither a parameter or
>> destructured binding, `nameof y` should just evaluate to `"y"`. This
>> should be agnostic to whether the binding has been declared yet, so in
>> your example, `x` should be set to `"y"`.
>> - If `y` is entirely undeclared, it should be a runtime
>> `ReferenceError` in the same way it is when accessing undefined
>> globals. So in your second example, I'd expect it to throw before even
>> attempting assignment
>>
>> -
>>
>> Isiah Meadows
>> cont...@isiahmeadows.com
>> www.isiahmeadows.com
>>
>> On Sun, Jun 16, 2019 at 12:00 AM guest271314 wrote:
>> >
>> > ```
>> > const x = nameof y
>> > const y = 1;
>> > ```
>> >
>> > At line 1 adjacent to ```nameof``` how does the user even know that there
>> > is a variable that will be declared named ```y```?
>> >
>> > What is the output of ```x``` where there is no variable named ```y```
>> > later declared?
>> >
>> > ```
>> > const x = nameof y
>> > const z = 1;
>> > ```
>> >
>> > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton
>> > wrote:
>> >>
>> >> > What should occur where the code is
>> >>
>> >> It would be "y" in all 3 places.
>> >>
>> >> > ... is a proposal for _more_ than only getting the _name_ of an
>> >> > _declared_ and _initialized_ variable?
>> >>
>> >> It is a proposal for getting the name of a _declared_ variable. Whether
>> >> it is _initialized_ does not matter.
>> >>
>> >> > Should a ```RefefenceError``` _not_ be thrown simple because
>> >> > ```nameof``` is used?
>> >>
>> >> No, an error is not thrown. ECMAScript is much more nuanced. Block scoped
>> >> variables from 'let' or 'const' exist and can be *referenced* (via
>> >> closure or export, currently) anywhere within the same block scope, even
>> >> before they are initialized. Until they have been *initialized* (the line
>> >> of code contain the declaration has been reached and evaluated), they
>> >> exist in a "Temporal Dead Zone" (TDZ). Attempting to *dereference* them
>> >> (i.e. access or store a value) while in this TDZ is what results in the
>> >> ReferenceError.
>> >>
>> >> At no point does the `nameof` operator *dereference* the v
Re: Re: What do you think about a C# 6 like nameof() expression for
> You have ignored the context from Jordan’s email (emphasis added):
>> again, `Object.keys({ y })[0]` will give you the string `y`, and will
survive *refactoring tools*. you can even do `function nameof(obj) { return
Object.keys(obj)[0]; }` and then `nameof({ y })`.
No, did not _ignore_ the context of the email.
Simply have no reference point for relying on an external tool, that is,
essentially a text editor, to write and dynamically "refactor" code. Here,
the code will be tested outside of the text editor in short order once
composed.
Was able to rename text at Mousepad and record the entire process within 20
seconds without needing to use ```nameof``` and without encountering any
issues such as mispelling the variable name or the text editor trying to
independently determine what the words am typing mean. The text editor is
just - a text editor.
Perhaps other JavaScript users who rely on "*refactoring tools*" and
"rename refactoring" in an IDE can relate. Not able to gather the
significance of ```nameof``` here - as in each case the user has to write
the name of the variable anyway. To each their own.
> VSCode is a popular editor that supports JavaScript **and** is a
refactoring tool. Rename refactoring was the subject I was responding to.
Was not previously aware or did not realize that the _individual choice_ to
use a particular text editor was a substantial reason to ask for change to
the entire JavaScript language in order for specific users to be able to
interact with an entirely different language.
If VSCode is particularly "popular" why cannot VSCode be specified and
implemented by and for the users who rely on the text editor to interpret
what the users' intent is when writing code.
In that case ```mkvmerge``` should be specified as a JavaScript method.
```webm``` is a "popular" (cannot help but to recollect "Popularity"
https://brendaneich.com/2008/04/popularity/) video container that is a
subset of the Matroska container, where if that method were specified in
JavaScript a user would be able to do ```mkvmerge({w: true, o:
"int_all.webm": i: ["int.webm", "int1.webm", "intN.webm"]})``` instead
of ```$ mkvmerge -w -o int_all.webm int.webm + int1.webm``` at
```terminal```.
On Mon, Jun 17, 2019 at 11:29 PM Ron Buckton
wrote:
> > How is VSCode related to JavaScript?
>
>
>
> You have ignored the context from Jordan’s email (emphasis added):
>
>
>
> >> again, `Object.keys({ y })[0]` will give you the string `y`, and will
> survive *refactoring tools*. you can even do `function nameof(obj) {
> return Object.keys(obj)[0]; }` and then `nameof({ y })`.
>
>
>
> VSCode is a popular editor that supports JavaScript **and** is a
> refactoring tool. Rename refactoring was the subject I was responding to.
>
>
>
> There are a number of reasons VSCode has implemented rename refactoring in
> this fashion. Not the least of which is that an editor cannot fully
> understand user intent. Let us say, for example, you are working with Gulp:
>
>
>
> ```
>
> const cwd /*1*/ = ".";
>
> gulp.src("*.js", { cwd /*2*/ });
>
> ```
>
>
>
> If you were to rename `cwd` at (1) and it **also** renamed the `cwd`
> property at (2), you would have introduced an error in the call because a
> `cwd` option to gulp has a special meaning. Since the editor doesn’t know
> the intent of the user may be to rename **both** symbols, it remains
> conservative and choses only to rename the binding and its references,
> producing:
>
>
>
> ```
>
> const currentDir = ".";
>
> gulp.src("*.js", { cwd: currentDir });
>
> ```
>
>
>
> There is also the issue of collisions:
>
>
>
> ```
>
> const foo /*1*/ = 1;
>
> f({ foo /*2*/, bar: 2 });
>
> ```
>
>
>
> If I were to use a refactoring tool to rename `foo` at (1) to `bar`, it
> would **not** be safe to rename the property at (2) as well as it would
> introduce a semantic error that would prevent the entire script from
> executing.
>
>
>
> In the context of Jordan’s email, that means that `Object.keys({ y })[0]`
> would **not** necessarily survive refactoring tools.
>
>
>
> *From:* es-discuss * On Behalf Of *
> guest271314
> *Sent:* Monday, June 17, 2019 7:40 AM
> *Cc:* es-discuss@mozilla.org
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> > In VSCode, if you rename ‘foo’ to ‘bar’ at /*1*/, you get this:
>
>
>
> How is VSCode related to JavaScript?
>
>
>
> Is the proposal really based on creating ```nameof``` in JavaScript to
> workaround output at a text editor?
>
>
>
> Why not file a bug with the individuals who write the code for VSCode or
> just write a text editor code from scratch which does what you want as to
> "refactoring". Or write the code by hand and test the code to avoid having
> to rely on _any_ text editor to catch your mistakes?
>
>
>
>
>
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
RE: Re: What do you think about a C# 6 like nameof() expression for
> … there'd need to be overwhelming evidence that this pattern is commonly used
> enough …
As it pertains to C#: https://github.com/search?l=C%23=nameof=Code.
There are at least 860k uses of the `nameof` operator in C# projects on GitHub,
and that’s before GitHub search gave up because there were too many results and
the search took too long:
[cid:image001.png@01D5252A.DFBBAB10]
There’s unfortunately no way to check for this pattern in JavaScript because
the feature doesn’t exist.
From: es-discuss On Behalf Of Jordan Harband
Sent: Sunday, June 16, 2019 10:35 PM
To: Frederick Stark
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
again, `Object.keys({ y })[0]` will give you the string `y`, and will survive
refactoring tools. you can even do `function nameof(obj) { return
Object.keys(obj)[0]; }` and then `nameof({ y })`.
Obviously it's slightly less ergonomic than `nameof y` would be - but adding
new syntax is very expensive, so there'd need to be overwhelming evidence that
this pattern is commonly used enough, and that userland workarounds like my
`nameof` function were insufficient.
On Sun, Jun 16, 2019 at 10:13 PM Frederick Stark
mailto:coagm...@gmail.com>> wrote:
> > your examples are all completely incorrect anyway
> "incorrect" as to precisely what?
Keep reading the email mate.
Incorrect as to your understanding of how the language works and at what point
variables are defined.
> The user MUST _already_ know the _exact_ identifier name
It's not an issue to need to know the name of the identifier. In fact, as you
correctly pointed out, it's necessary.
If I'm understanding it correctly, the value of the proposal is to make it
easier to refactor (especially with variable renaming tools) without leaving
behind string literals that no longer match the variable name.
I've run into this issue before, but it's been a relatively minor pain for me
personally. So I can see some use for the proposal, though I suspect it would
see most of it's use in tooling.
On the other hand, it might add unnecessary complexity to the language, which
should be avoided.
Overall I'm very mildly supportive.
> That leaves the use case of getting ALL of the names of the identifiers in
> the current scope
I have not seen anyone proposing this, so there's no reason to criticize it yet.
Obligatory disclaimer: not a TC39 member, no decision making power or influence
on process
On Jun 17 2019, at 2:42 pm, guest271314
mailto:guest271...@gmail.com>> wrote:
The user MUST _already_ know the _exact_ identifier name or an error will be
thrown for the original proposal and additional use case for ```nameof```
const x = nameof y; // "y"
const y = 1;
making the need for ```nameof``` moot given that the user cannot then
rationally state that the identifier as a _string_ will somehow be mispelled if
they are able to write the _exact_ name of the identifer at ```nameof``` 100%
of the time.
That leaves the use case of getting ALL of the names of the identifiers in the
current scope
// NAMEOF is always dynamic list of let, const declarations in current scope
console.log(NAMEOF); // ["x", "y"]; [{name:"x", line:5}, {name:"y", line:7}]
// should resolve be in the list even if not declared using const or let?
await new Promise(resolve => setTimeout(resolve, Math.floor(Math.random() *
1000)));
const x = nameof y
await new Promise(resolve => setTimeout(resolve, Math.floor(Math.random() *
1000)));
const y = 1;
without having to already know the name of the identifiers, as is required by
the original proposal, which essentially negates itself as the string literal
```'y'``` is briefer than ```nameof y```.
On Mon, Jun 17, 2019 at 4:19 AM Frederick Stark
mailto:coagm...@gmail.com>> wrote:
guest271314, your examples are all completely incorrect anyway since all
variable declarations (including let and const) are hoisted to the top of the
scope, so when nameof y is evaluated, y is already declared in the scope.
The special behaviour introduced with let and const is that they set up a
"Temporal Dead Zone" where attempts to set or get their value before the line
where they are declared in code throws an exception.
Since nameof doesn't care about the value, only the name of the variable, it
would not need to throw an exception.
Of course, were this proposal to be taken seriously, it could be specced either
way
On Jun 17 2019, at 10:15 am, guest271314
mailto:guest271...@gmail.com>> wrote:
> - If `y` is directly visible in scope and is neither a parameter or
destructured binding, `nameof y` should just evaluate to `"y"`. This
should be agnostic to whether the binding has been declared yet, so in
your example, `x` should be set to `"y"`.
The 1st question at
https://esdiscuss.org/topic/what-do-you-think-abou
RE: Re: What do you think about a C# 6 like nameof() expression for
> How is VSCode related to JavaScript?
You have ignored the context from Jordan’s email (emphasis added):
>> again, `Object.keys({ y })[0]` will give you the string `y`, and will
>> survive refactoring tools. you can even do `function nameof(obj) { return
>> Object.keys(obj)[0]; }` and then `nameof({ y })`.
VSCode is a popular editor that supports JavaScript *and* is a refactoring
tool. Rename refactoring was the subject I was responding to.
There are a number of reasons VSCode has implemented rename refactoring in this
fashion. Not the least of which is that an editor cannot fully understand user
intent. Let us say, for example, you are working with Gulp:
```
const cwd /*1*/ = ".";
gulp.src("*.js", { cwd /*2*/ });
```
If you were to rename `cwd` at (1) and it *also* renamed the `cwd` property at
(2), you would have introduced an error in the call because a `cwd` option to
gulp has a special meaning. Since the editor doesn’t know the intent of the
user may be to rename *both* symbols, it remains conservative and choses only
to rename the binding and its references, producing:
```
const currentDir = ".";
gulp.src("*.js", { cwd: currentDir });
```
There is also the issue of collisions:
```
const foo /*1*/ = 1;
f({ foo /*2*/, bar: 2 });
```
If I were to use a refactoring tool to rename `foo` at (1) to `bar`, it would
*not* be safe to rename the property at (2) as well as it would introduce a
semantic error that would prevent the entire script from executing.
In the context of Jordan’s email, that means that `Object.keys({ y })[0]` would
*not* necessarily survive refactoring tools.
From: es-discuss On Behalf Of guest271314
Sent: Monday, June 17, 2019 7:40 AM
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
> In VSCode, if you rename ‘foo’ to ‘bar’ at /1/, you get this:
How is VSCode related to JavaScript?
Is the proposal really based on creating ```nameof``` in JavaScript to
workaround output at a text editor?
Why not file a bug with the individuals who write the code for VSCode or just
write a text editor code from scratch which does what you want as to
"refactoring". Or write the code by hand and test the code to avoid having to
rely on _any_ text editor to catch your mistakes?
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
> In VSCode, if you rename ‘foo’ to ‘bar’ at /*1*/, you get this: How is VSCode related to JavaScript? Is the proposal really based on creating ```nameof``` in JavaScript to workaround output at a text editor? Why not file a bug with the individuals who write the code for VSCode or just write a text editor code from scratch which does what you want as to "refactoring". Or write the code by hand and test the code to avoid having to rely on _any_ text editor to catch your mistakes? ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
RE: Re: What do you think about a C# 6 like nameof() expression for
> `Object.keys({ y })[0]` will give you the string `y`, and will survive
> refactoring tools
No it won’t. Given the following:
```
let foo /*1*/ = 1;
let x = { foo /*2*/ };
```
In VSCode, if you rename ‘foo’ to ‘bar’ at /*1*/, you get this:
```
let bar = 1;
let x = { foo: bar };
```
If you rename ‘foo’ to ‘bar’ at /*2*/, you get this:
```
let foo = 1;
let x = { bar: foo };
```
Rename only renames one side of the symbol, either the property name or the
captured binding, but not both.
From: es-discuss On Behalf Of Jordan Harband
Sent: Sunday, June 16, 2019 10:35 PM
To: Frederick Stark
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
again, `Object.keys({ y })[0]` will give you the string `y`, and will survive
refactoring tools. you can even do `function nameof(obj) { return
Object.keys(obj)[0]; }` and then `nameof({ y })`.
Obviously it's slightly less ergonomic than `nameof y` would be - but adding
new syntax is very expensive, so there'd need to be overwhelming evidence that
this pattern is commonly used enough, and that userland workarounds like my
`nameof` function were insufficient.
On Sun, Jun 16, 2019 at 10:13 PM Frederick Stark
mailto:coagm...@gmail.com>> wrote:
> > your examples are all completely incorrect anyway
> "incorrect" as to precisely what?
Keep reading the email mate.
Incorrect as to your understanding of how the language works and at what point
variables are defined.
> The user MUST _already_ know the _exact_ identifier name
It's not an issue to need to know the name of the identifier. In fact, as you
correctly pointed out, it's necessary.
If I'm understanding it correctly, the value of the proposal is to make it
easier to refactor (especially with variable renaming tools) without leaving
behind string literals that no longer match the variable name.
I've run into this issue before, but it's been a relatively minor pain for me
personally. So I can see some use for the proposal, though I suspect it would
see most of it's use in tooling.
On the other hand, it might add unnecessary complexity to the language, which
should be avoided.
Overall I'm very mildly supportive.
> That leaves the use case of getting ALL of the names of the identifiers in
> the current scope
I have not seen anyone proposing this, so there's no reason to criticize it yet.
Obligatory disclaimer: not a TC39 member, no decision making power or influence
on process
On Jun 17 2019, at 2:42 pm, guest271314
mailto:guest271...@gmail.com>> wrote:
The user MUST _already_ know the _exact_ identifier name or an error will be
thrown for the original proposal and additional use case for ```nameof```
const x = nameof y; // "y"
const y = 1;
making the need for ```nameof``` moot given that the user cannot then
rationally state that the identifier as a _string_ will somehow be mispelled if
they are able to write the _exact_ name of the identifer at ```nameof``` 100%
of the time.
That leaves the use case of getting ALL of the names of the identifiers in the
current scope
// NAMEOF is always dynamic list of let, const declarations in current scope
console.log(NAMEOF); // ["x", "y"]; [{name:"x", line:5}, {name:"y", line:7}]
// should resolve be in the list even if not declared using const or let?
await new Promise(resolve => setTimeout(resolve, Math.floor(Math.random() *
1000)));
const x = nameof y
await new Promise(resolve => setTimeout(resolve, Math.floor(Math.random() *
1000)));
const y = 1;
without having to already know the name of the identifiers, as is required by
the original proposal, which essentially negates itself as the string literal
```'y'``` is briefer than ```nameof y```.
On Mon, Jun 17, 2019 at 4:19 AM Frederick Stark
mailto:coagm...@gmail.com>> wrote:
guest271314, your examples are all completely incorrect anyway since all
variable declarations (including let and const) are hoisted to the top of the
scope, so when nameof y is evaluated, y is already declared in the scope.
The special behaviour introduced with let and const is that they set up a
"Temporal Dead Zone" where attempts to set or get their value before the line
where they are declared in code throws an exception.
Since nameof doesn't care about the value, only the name of the variable, it
would not need to throw an exception.
Of course, were this proposal to be taken seriously, it could be specced either
way
On Jun 17 2019, at 10:15 am, guest271314
mailto:guest271...@gmail.com>> wrote:
> - If `y` is directly visible in scope and is neither a parameter or
destructured binding, `nameof y` should just evaluate to `"y"`. This
should be agnostic to whether the binding has been declared yet, so in
your example, `x` should be set to `"y"`.
The 1st question at
https://esdiscuss.org/topic/what-do-you-think-abou
Re: Re: What do you think about a C# 6 like nameof() expression for
ing, `nameof y` should just evaluate to `"y"`. This
> should be agnostic to whether the binding has been declared yet, so in
> your example, `x` should be set to `"y"`.
> - If `y` is entirely undeclared, it should be a runtime
> `ReferenceError` in the same way it is when accessing undefined
> globals. So in your second example, I'd expect it to throw before even
> attempting assignment
>
> -
>
> Isiah Meadows
> cont...@isiahmeadows.com
> www.isiahmeadows.com
>
> On Sun, Jun 16, 2019 at 12:00 AM guest271314
> wrote:
> >
> > ```
> > const x = nameof y
> > const y = 1;
> > ```
> >
> > At line 1 adjacent to ```nameof``` how does the user even know that
> there is a variable that will be declared named ```y```?
> >
> > What is the output of ```x``` where there is no variable named ```y```
> later declared?
> >
> > ```
> > const x = nameof y
> > const z = 1;
> > ```
> >
> > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton
> wrote:
> >>
> >> > What should occur where the code is
> >>
> >> It would be "y" in all 3 places.
> >>
> >> > ... is a proposal for _more_ than only getting the _name_ of an
> _declared_ and _initialized_ variable?
> >>
> >> It is a proposal for getting the name of a _declared_ variable. Whether
> it is _initialized_ does not matter.
> >>
> >> > Should a ```RefefenceError``` _not_ be thrown simple because
> ```nameof``` is used?
> >>
> >> No, an error is not thrown. ECMAScript is much more nuanced. Block
> scoped variables from 'let' or 'const' exist and can be *referenced* (via
> closure or export, currently) anywhere within the same block scope, even
> before they are initialized. Until they have been *initialized* (the line
> of code contain the declaration has been reached and evaluated), they exist
> in a "Temporal Dead Zone" (TDZ). Attempting to *dereference* them (i.e.
> access or store a value) while in this TDZ is what results in the
> ReferenceError.
> >>
> >> At no point does the `nameof` operator *dereference* the variable, so
> no error need be thrown.
> >>
> >> From: guest271314
> >> Sent: Saturday, June 15, 4:29 PM
> >> Subject: Re: Re: What do you think about a C# 6 like nameof()
> expression for
> >> To: Ron Buckton
> >> Cc: es-discuss@mozilla.org
> >>
> >>
> >>
> >>
> >> What should occur where the code is
> >>
> >> ```
> >> const x = nameof y
> >> await new Promise(resolve => setTimeout(resolve, 10)); // should x
> be "y" here?
> >> await new Promise(resolve => setTimeout(resolve, 20)); // should x
> be "y" here?
> >> await Promise.all([new Promise(resolve => setTimeout(resolve, 30)),
> ...doStuff()]); // should x be "y" here?
> >> const y = 1;
> >> ```
> >>
> >> ?
> >>
> >> The immediately invoked arrow function example (where a
> ```RefeferenceError``` is thrown) appears to demonstrate that to output the
> expected result of ```nameof``` within the context of the code example
> >>
> >> ```
> >> const x = nameof y
> >> const y = 1;
> >> ```
> >>
> >> is a proposal for _more_ than only getting the _name_ of an _declared_
> and _initialized_ variable?
> >>
> >> Should a ```RefefenceError``` _not_ be thrown simple because
> ```nameof``` is used?
> >>
> >> On Sat, Jun 15, 2019 at 11:16 PM Ron Buckton
> wrote:
> >>
> >> ```
> >> const x = nameof y
> >> const y = 1;
> >> ```
> >>
> >> `x` would have the value “y”. It would not matter if `y` were
> initialized or had yet been reached during execution. It does not deviate
> from the purpose of `let` or `const`, because you are not accessing the
> value of the identifier.
> >>
> >> Also consider that this is legal ECMAScript in a module:
> >>
> >> ```
> >> export { y }
> >> const y = 1;
> >> ```
> >>
> >> The binding for `y` exists within the same block scope, it just has not
> yet been initialized. Exporting it via `export { y }`, closing over it via
> `() => y`, or accessing it via `nameof y` would all be the same. In all
> three cases you are accessing the *binding* of `y`, not the *value* of `y`.
> Even in the `() => y` case, you don’t access the *value* of `y` until you
> execute the function.
> >>
> >&g
Re: Re: What do you think about a C# 6 like nameof() expression for
y` is entirely undeclared, it should be a runtime > > > > `ReferenceError` in the same way it is when accessing undefined > > > > globals. So in your second example, I'd expect it to throw before even > > > > attempting assignment > > > > > > > > - > > > > Isiah Meadows > > > > cont...@isiahmeadows.com (mailto:cont...@isiahmeadows.com) > > > > www.isiahmeadows.com (http://www.isiahmeadows.com) > > > > > > > > On Sun, Jun 16, 2019 at 12:00 AM guest271314 > > > (mailto:guest271...@gmail.com)> wrote: > > > > > > > > > > ``` > > > > > const x = nameof y > > > > > const y = 1; > > > > > ``` > > > > > > > > > > At line 1 adjacent to ```nameof``` how does the user even know that > > > > > there is a variable that will be declared named ```y```? > > > > > > > > > > What is the output of ```x``` where there is no variable named > > > > > ```y``` later declared? > > > > > > > > > > ``` > > > > > const x = nameof y > > > > > const z = 1; > > > > > ``` > > > > > > > > > > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton > > > > > mailto:ron.buck...@microsoft.com)> wrote: > > > > >> > > > > >> > What should occur where the code is > > > > >> > > > > >> It would be "y" in all 3 places. > > > > >> > > > > >> > ... is a proposal for _more_ than only getting the _name_ of an > > > > >> > _declared_ and _initialized_ variable? > > > > >> > > > > >> It is a proposal for getting the name of a _declared_ variable. > > > > >> Whether it is _initialized_ does not matter. > > > > >> > > > > >> > Should a ```RefefenceError``` _not_ be thrown simple because > > > > >> > ```nameof``` is used? > > > > >> > > > > >> No, an error is not thrown. ECMAScript is much more nuanced. Block > > > > >> scoped variables from 'let' or 'const' exist and can be *referenced* > > > > >> (via closure or export, currently) anywhere within the same block > > > > >> scope, even before they are initialized. Until they have been > > > > >> *initialized* (the line of code contain the declaration has been > > > > >> reached and evaluated), they exist in a "Temporal Dead Zone" (TDZ). > > > > >> Attempting to *dereference* them (i.e. access or store a value) > > > > >> while in this TDZ is what results in the ReferenceError. > > > > >> > > > > >> At no point does the `nameof` operator *dereference* the variable, > > > > >> so no error need be thrown. > > > > >> > > > > >> From: guest271314 > > > > >> Sent: Saturday, June 15, 4:29 PM > > > > >> Subject: Re: Re: What do you think about a C# 6 like nameof() > > > > >> expression for > > > > >> To: Ron Buckton > > > > >> Cc: es-discuss@mozilla.org (mailto:es-discuss@mozilla.org) > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> What should occur where the code is > > > > >> > > > > >> ``` > > > > >> const x = nameof y > > > > >> await new Promise(resolve => setTimeout(resolve, 10)); // should > > > > >> x be "y" here? > > > > >> await new Promise(resolve => setTimeout(resolve, 20)); // should > > > > >> x be "y" here? > > > > >> await Promise.all([new Promise(resolve => setTimeout(resolve, > > > > >> 30)), ...doStuff()]); // should x be "y" here? > > > > >> const y = 1; > > > > >> ``` > > > > >> > > > > >> ? > > > > >> > > > > >> The immediately invoked arrow function example (where a > > > > >> ```RefeferenceError``` is thrown) appears to demonstrate that to > > > > >> output the expected result of ```nameof``` within the context of the > > > > >> code example > > > > >> > > > > >> ``` > &g
Re: Re: What do you think about a C# 6 like nameof() expression for
The user MUST _already_ know the _exact_ identifier name or an error will
be thrown for the original proposal and additional use case for ```nameof```
const x = nameof y; // "y"
const y = 1;
making the need for ```nameof``` moot given that the user cannot then
rationally state that the identifier as a _string_ will somehow be
mispelled if they are able to write the _exact_ name of the identifer at
```nameof``` 100% of the time.
That leaves the use case of getting ALL of the names of the identifiers in
the current scope
// NAMEOF is always dynamic list of let, const declarations in current scope
console.log(NAMEOF); // ["x", "y"]; [{name:"x", line:5}, {name:"y", line:7}]
// should resolve be in the list even if not declared using const or let?
await new Promise(resolve => setTimeout(resolve,
Math.floor(Math.random() * 1000)));
const x = nameof y
await new Promise(resolve => setTimeout(resolve,
Math.floor(Math.random() * 1000)));
const y = 1;
without having to already know the name of the identifiers, as is required
by the original proposal, which essentially negates itself as the string
literal ```'y'``` is briefer than ```nameof y```.
On Mon, Jun 17, 2019 at 4:19 AM Frederick Stark wrote:
> guest271314, your examples are all completely incorrect anyway since all
> variable declarations (including let and const) are hoisted to the top of
> the scope, so when nameof y is evaluated, y is already declared in the
> scope.
>
> The special behaviour introduced with let and const is that they set up a
> "Temporal Dead Zone" where attempts to set or get their value before the
> line where they are declared in code throws an exception.
> Since nameof doesn't care about the value, only the name of the variable,
> it would not *need* to throw an exception.
> Of course, were this proposal to be taken seriously, it could be specced
> either way
>
> On Jun 17 2019, at 10:15 am, guest271314 wrote:
>
> > - If `y` is directly visible in scope and is neither a parameter or
> destructured binding, `nameof y` should just evaluate to `"y"`. This
> should be agnostic to whether the binding has been declared yet, so in
> your example, `x` should be set to `"y"`.
>
> The 1st question at
> https://esdiscuss.org/topic/what-do-you-think-about-a-c-6-like-nameof-expression-for#content-33
> remains:
>
> Without having composed or previously read the source code, at line 1
> adjacent to ```nameof``` how does the user know that there will be later
> declared variable named ```y```?
>
>
>
> On Sun, Jun 16, 2019 at 7:04 AM Isiah Meadows
> wrote:
>
> Here's my opinion:
>
> - If `y` is directly visible in scope and is neither a parameter or
> destructured binding, `nameof y` should just evaluate to `"y"`. This
> should be agnostic to whether the binding has been declared yet, so in
> your example, `x` should be set to `"y"`.
> - If `y` is entirely undeclared, it should be a runtime
> `ReferenceError` in the same way it is when accessing undefined
> globals. So in your second example, I'd expect it to throw before even
> attempting assignment
>
> -
>
> Isiah Meadows
> cont...@isiahmeadows.com
> www.isiahmeadows.com
>
> On Sun, Jun 16, 2019 at 12:00 AM guest271314
> wrote:
> >
> > ```
> > const x = nameof y
> > const y = 1;
> > ```
> >
> > At line 1 adjacent to ```nameof``` how does the user even know that
> there is a variable that will be declared named ```y```?
> >
> > What is the output of ```x``` where there is no variable named ```y```
> later declared?
> >
> > ```
> > const x = nameof y
> > const z = 1;
> > ```
> >
> > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton
> wrote:
> >>
> >> > What should occur where the code is
> >>
> >> It would be "y" in all 3 places.
> >>
> >> > ... is a proposal for _more_ than only getting the _name_ of an
> _declared_ and _initialized_ variable?
> >>
> >> It is a proposal for getting the name of a _declared_ variable. Whether
> it is _initialized_ does not matter.
> >>
> >> > Should a ```RefefenceError``` _not_ be thrown simple because
> ```nameof``` is used?
> >>
> >> No, an error is not thrown. ECMAScript is much more nuanced. Block
> scoped variables from 'let' or 'const' exist and can be *referenced* (via
> closure or export, currently) anywhere within the same block scope, even
> before they are initialized. Until they have been *initialized* (the line
> of code contain the declaration has been reached and evaluated), they exist
> in a "Temporal Dead Zone"
Re: Re: What do you think about a C# 6 like nameof() expression for
> your examples are all completely incorrect anyway "incorrect" as to precisely what? On Mon, Jun 17, 2019 at 4:19 AM Frederick Stark wrote: > guest271314, your examples are all completely incorrect anyway since all > variable declarations (including let and const) are hoisted to the top of > the scope, so when nameof y is evaluated, y is already declared in the > scope. > > The special behaviour introduced with let and const is that they set up a > "Temporal Dead Zone" where attempts to set or get their value before the > line where they are declared in code throws an exception. > Since nameof doesn't care about the value, only the name of the variable, > it would not *need* to throw an exception. > Of course, were this proposal to be taken seriously, it could be specced > either way > > On Jun 17 2019, at 10:15 am, guest271314 wrote: > > > - If `y` is directly visible in scope and is neither a parameter or > destructured binding, `nameof y` should just evaluate to `"y"`. This > should be agnostic to whether the binding has been declared yet, so in > your example, `x` should be set to `"y"`. > > The 1st question at > https://esdiscuss.org/topic/what-do-you-think-about-a-c-6-like-nameof-expression-for#content-33 > remains: > > Without having composed or previously read the source code, at line 1 > adjacent to ```nameof``` how does the user know that there will be later > declared variable named ```y```? > > > > On Sun, Jun 16, 2019 at 7:04 AM Isiah Meadows > wrote: > > Here's my opinion: > > - If `y` is directly visible in scope and is neither a parameter or > destructured binding, `nameof y` should just evaluate to `"y"`. This > should be agnostic to whether the binding has been declared yet, so in > your example, `x` should be set to `"y"`. > - If `y` is entirely undeclared, it should be a runtime > `ReferenceError` in the same way it is when accessing undefined > globals. So in your second example, I'd expect it to throw before even > attempting assignment > > - > > Isiah Meadows > cont...@isiahmeadows.com > www.isiahmeadows.com > > On Sun, Jun 16, 2019 at 12:00 AM guest271314 > wrote: > > > > ``` > > const x = nameof y > > const y = 1; > > ``` > > > > At line 1 adjacent to ```nameof``` how does the user even know that > there is a variable that will be declared named ```y```? > > > > What is the output of ```x``` where there is no variable named ```y``` > later declared? > > > > ``` > > const x = nameof y > > const z = 1; > > ``` > > > > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton > wrote: > >> > >> > What should occur where the code is > >> > >> It would be "y" in all 3 places. > >> > >> > ... is a proposal for _more_ than only getting the _name_ of an > _declared_ and _initialized_ variable? > >> > >> It is a proposal for getting the name of a _declared_ variable. Whether > it is _initialized_ does not matter. > >> > >> > Should a ```RefefenceError``` _not_ be thrown simple because > ```nameof``` is used? > >> > >> No, an error is not thrown. ECMAScript is much more nuanced. Block > scoped variables from 'let' or 'const' exist and can be *referenced* (via > closure or export, currently) anywhere within the same block scope, even > before they are initialized. Until they have been *initialized* (the line > of code contain the declaration has been reached and evaluated), they exist > in a "Temporal Dead Zone" (TDZ). Attempting to *dereference* them (i.e. > access or store a value) while in this TDZ is what results in the > ReferenceError. > >> > >> At no point does the `nameof` operator *dereference* the variable, so > no error need be thrown. > >> > >> From: guest271314 > >> Sent: Saturday, June 15, 4:29 PM > >> Subject: Re: Re: What do you think about a C# 6 like nameof() > expression for > >> To: Ron Buckton > >> Cc: es-discuss@mozilla.org > >> > >> > >> > >> > >> What should occur where the code is > >> > >> ``` > >> const x = nameof y > >> await new Promise(resolve => setTimeout(resolve, 10)); // should x > be "y" here? > >> await new Promise(resolve => setTimeout(resolve, 20)); // should x > be "y" here? > >> await Promise.all([new Promise(resolve => setTimeout(resolve, 30)), > ...doStuff()]); // should x be "y" here? > >> const y = 1; > >>
Re: Re: What do you think about a C# 6 like nameof() expression for
guest271314, your examples are all completely incorrect anyway since all variable declarations (including let and const) are hoisted to the top of the scope, so when nameof y is evaluated, y is already declared in the scope. The special behaviour introduced with let and const is that they set up a "Temporal Dead Zone" where attempts to set or get their value before the line where they are declared in code throws an exception. Since nameof doesn't care about the value, only the name of the variable, it would not need to throw an exception. Of course, were this proposal to be taken seriously, it could be specced either way On Jun 17 2019, at 10:15 am, guest271314 wrote: > > - If `y` is directly visible in scope and is neither a parameter or > destructured binding, `nameof y` should just evaluate to `"y"`. This > should be agnostic to whether the binding has been declared yet, so in > your example, `x` should be set to `"y"`. > > The 1st question at > https://esdiscuss.org/topic/what-do-you-think-about-a-c-6-like-nameof-expression-for#content-33 > remains: > > Without having composed or previously read the source code, at line 1 > adjacent to ```nameof``` how does the user know that there will be later > declared variable named ```y```? > > > > On Sun, Jun 16, 2019 at 7:04 AM Isiah Meadows (mailto:isiahmead...@gmail.com)> wrote: > > Here's my opinion: > > > > - If `y` is directly visible in scope and is neither a parameter or > > destructured binding, `nameof y` should just evaluate to `"y"`. This > > should be agnostic to whether the binding has been declared yet, so in > > your example, `x` should be set to `"y"`. > > - If `y` is entirely undeclared, it should be a runtime > > `ReferenceError` in the same way it is when accessing undefined > > globals. So in your second example, I'd expect it to throw before even > > attempting assignment > > > > - > > Isiah Meadows > > cont...@isiahmeadows.com (mailto:cont...@isiahmeadows.com) > > www.isiahmeadows.com (http://www.isiahmeadows.com) > > > > On Sun, Jun 16, 2019 at 12:00 AM guest271314 > (mailto:guest271...@gmail.com)> wrote: > > > > > > ``` > > > const x = nameof y > > > const y = 1; > > > ``` > > > > > > At line 1 adjacent to ```nameof``` how does the user even know that there > > > is a variable that will be declared named ```y```? > > > > > > What is the output of ```x``` where there is no variable named ```y``` > > > later declared? > > > > > > ``` > > > const x = nameof y > > > const z = 1; > > > ``` > > > > > > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton > > (mailto:ron.buck...@microsoft.com)> wrote: > > >> > > >> > What should occur where the code is > > >> > > >> It would be "y" in all 3 places. > > >> > > >> > ... is a proposal for _more_ than only getting the _name_ of an > > >> > _declared_ and _initialized_ variable? > > >> > > >> It is a proposal for getting the name of a _declared_ variable. Whether > > >> it is _initialized_ does not matter. > > >> > > >> > Should a ```RefefenceError``` _not_ be thrown simple because > > >> > ```nameof``` is used? > > >> > > >> No, an error is not thrown. ECMAScript is much more nuanced. Block > > >> scoped variables from 'let' or 'const' exist and can be *referenced* > > >> (via closure or export, currently) anywhere within the same block scope, > > >> even before they are initialized. Until they have been *initialized* > > >> (the line of code contain the declaration has been reached and > > >> evaluated), they exist in a "Temporal Dead Zone" (TDZ). Attempting to > > >> *dereference* them (i.e. access or store a value) while in this TDZ is > > >> what results in the ReferenceError. > > >> > > >> At no point does the `nameof` operator *dereference* the variable, so no > > >> error need be thrown. > > >> > > >> From: guest271314 > > >> Sent: Saturday, June 15, 4:29 PM > > >> Subject: Re: Re: What do you think about a C# 6 like nameof() expression > > >> for > > >> To: Ron Buckton > > >> Cc: es-discuss@mozilla.org (mailto:es-discuss@mozilla.org) > > >> > > >> > > >> > > >> > > >> What should occur where the code is > > &g
Re: Re: What do you think about a C# 6 like nameof() expression for
> - If `y` is directly visible in scope and is neither a parameter or destructured binding, `nameof y` should just evaluate to `"y"`. This should be agnostic to whether the binding has been declared yet, so in your example, `x` should be set to `"y"`. The 1st question at https://esdiscuss.org/topic/what-do-you-think-about-a-c-6-like-nameof-expression-for#content-33 remains: Without having composed or previously read the source code, at line 1 adjacent to ```nameof``` how does the user know that there will be later declared variable named ```y```? On Sun, Jun 16, 2019 at 7:04 AM Isiah Meadows wrote: > Here's my opinion: > > - If `y` is directly visible in scope and is neither a parameter or > destructured binding, `nameof y` should just evaluate to `"y"`. This > should be agnostic to whether the binding has been declared yet, so in > your example, `x` should be set to `"y"`. > - If `y` is entirely undeclared, it should be a runtime > `ReferenceError` in the same way it is when accessing undefined > globals. So in your second example, I'd expect it to throw before even > attempting assignment > > - > > Isiah Meadows > cont...@isiahmeadows.com > www.isiahmeadows.com > > On Sun, Jun 16, 2019 at 12:00 AM guest271314 > wrote: > > > > ``` > > const x = nameof y > > const y = 1; > > ``` > > > > At line 1 adjacent to ```nameof``` how does the user even know that > there is a variable that will be declared named ```y```? > > > > What is the output of ```x``` where there is no variable named ```y``` > later declared? > > > > ``` > > const x = nameof y > > const z = 1; > > ``` > > > > On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton > wrote: > >> > >> > What should occur where the code is > >> > >> It would be "y" in all 3 places. > >> > >> > ... is a proposal for _more_ than only getting the _name_ of an > _declared_ and _initialized_ variable? > >> > >> It is a proposal for getting the name of a _declared_ variable. Whether > it is _initialized_ does not matter. > >> > >> > Should a ```RefefenceError``` _not_ be thrown simple because > ```nameof``` is used? > >> > >> No, an error is not thrown. ECMAScript is much more nuanced. Block > scoped variables from 'let' or 'const' exist and can be *referenced* (via > closure or export, currently) anywhere within the same block scope, even > before they are initialized. Until they have been *initialized* (the line > of code contain the declaration has been reached and evaluated), they exist > in a "Temporal Dead Zone" (TDZ). Attempting to *dereference* them (i.e. > access or store a value) while in this TDZ is what results in the > ReferenceError. > >> > >> At no point does the `nameof` operator *dereference* the variable, so > no error need be thrown. > >> > >> From: guest271314 > >> Sent: Saturday, June 15, 4:29 PM > >> Subject: Re: Re: What do you think about a C# 6 like nameof() > expression for > >> To: Ron Buckton > >> Cc: es-discuss@mozilla.org > >> > >> > >> > >> > >> What should occur where the code is > >> > >> ``` > >> const x = nameof y > >> await new Promise(resolve => setTimeout(resolve, 10)); // should x > be "y" here? > >> await new Promise(resolve => setTimeout(resolve, 20)); // should x > be "y" here? > >> await Promise.all([new Promise(resolve => setTimeout(resolve, 30)), > ...doStuff()]); // should x be "y" here? > >> const y = 1; > >> ``` > >> > >> ? > >> > >> The immediately invoked arrow function example (where a > ```RefeferenceError``` is thrown) appears to demonstrate that to output the > expected result of ```nameof``` within the context of the code example > >> > >> ``` > >> const x = nameof y > >> const y = 1; > >> ``` > >> > >> is a proposal for _more_ than only getting the _name_ of an _declared_ > and _initialized_ variable? > >> > >> Should a ```RefefenceError``` _not_ be thrown simple because > ```nameof``` is used? > >> > >> On Sat, Jun 15, 2019 at 11:16 PM Ron Buckton > wrote: > >> > >> ``` > >> const x = nameof y > >> const y = 1; > >> ``` > >> > >> `x` would have the value “y”. It would not matter if `y` were > initialized or had yet been reached during execution. It does not deviate > from th
Re: Re: What do you think about a C# 6 like nameof() expression for
Here's my opinion:
- If `y` is directly visible in scope and is neither a parameter or
destructured binding, `nameof y` should just evaluate to `"y"`. This
should be agnostic to whether the binding has been declared yet, so in
your example, `x` should be set to `"y"`.
- If `y` is entirely undeclared, it should be a runtime
`ReferenceError` in the same way it is when accessing undefined
globals. So in your second example, I'd expect it to throw before even
attempting assignment
-
Isiah Meadows
cont...@isiahmeadows.com
www.isiahmeadows.com
On Sun, Jun 16, 2019 at 12:00 AM guest271314 wrote:
>
> ```
> const x = nameof y
> const y = 1;
> ```
>
> At line 1 adjacent to ```nameof``` how does the user even know that there is
> a variable that will be declared named ```y```?
>
> What is the output of ```x``` where there is no variable named ```y``` later
> declared?
>
> ```
> const x = nameof y
> const z = 1;
> ```
>
> On Sun, Jun 16, 2019 at 12:03 AM Ron Buckton
> wrote:
>>
>> > What should occur where the code is
>>
>> It would be "y" in all 3 places.
>>
>> > ... is a proposal for _more_ than only getting the _name_ of an _declared_
>> > and _initialized_ variable?
>>
>> It is a proposal for getting the name of a _declared_ variable. Whether it
>> is _initialized_ does not matter.
>>
>> > Should a ```RefefenceError``` _not_ be thrown simple because ```nameof```
>> > is used?
>>
>> No, an error is not thrown. ECMAScript is much more nuanced. Block scoped
>> variables from 'let' or 'const' exist and can be *referenced* (via closure
>> or export, currently) anywhere within the same block scope, even before they
>> are initialized. Until they have been *initialized* (the line of code
>> contain the declaration has been reached and evaluated), they exist in a
>> "Temporal Dead Zone" (TDZ). Attempting to *dereference* them (i.e. access or
>> store a value) while in this TDZ is what results in the ReferenceError.
>>
>> At no point does the `nameof` operator *dereference* the variable, so no
>> error need be thrown.
>>
>> From: guest271314
>> Sent: Saturday, June 15, 4:29 PM
>> Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
>> To: Ron Buckton
>> Cc: es-discuss@mozilla.org
>>
>>
>>
>>
>> What should occur where the code is
>>
>> ```
>> const x = nameof y
>> await new Promise(resolve => setTimeout(resolve, 10)); // should x be
>> "y" here?
>> await new Promise(resolve => setTimeout(resolve, 20)); // should x be
>> "y" here?
>> await Promise.all([new Promise(resolve => setTimeout(resolve, 30)),
>> ...doStuff()]); // should x be "y" here?
>> const y = 1;
>> ```
>>
>> ?
>>
>> The immediately invoked arrow function example (where a
>> ```RefeferenceError``` is thrown) appears to demonstrate that to output the
>> expected result of ```nameof``` within the context of the code example
>>
>> ```
>> const x = nameof y
>> const y = 1;
>> ```
>>
>> is a proposal for _more_ than only getting the _name_ of an _declared_ and
>> _initialized_ variable?
>>
>> Should a ```RefefenceError``` _not_ be thrown simple because ```nameof``` is
>> used?
>>
>> On Sat, Jun 15, 2019 at 11:16 PM Ron Buckton
>> wrote:
>>
>> ```
>> const x = nameof y
>> const y = 1;
>> ```
>>
>> `x` would have the value “y”. It would not matter if `y` were initialized or
>> had yet been reached during execution. It does not deviate from the purpose
>> of `let` or `const`, because you are not accessing the value of the
>> identifier.
>>
>> Also consider that this is legal ECMAScript in a module:
>>
>> ```
>> export { y }
>> const y = 1;
>> ```
>>
>> The binding for `y` exists within the same block scope, it just has not yet
>> been initialized. Exporting it via `export { y }`, closing over it via `()
>> => y`, or accessing it via `nameof y` would all be the same. In all three
>> cases you are accessing the *binding* of `y`, not the *value* of `y`. Even
>> in the `() => y` case, you don’t access the *value* of `y` until you execute
>> the function.
>>
>> From: guest271314
>> Sent: Saturday, June 15, 2019 3:57 PM
>> To: Ron Buckton
>> Cc: es-discuss@mozilla.org
>> Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
>>
>> >
Re: Re: What do you think about a C# 6 like nameof() expression for
I've got a few code bases where I do a lot of stuff like `func(person,
"person")`, and it'd be pretty useful to avoid the duplication.
I'd prefer something more direct like `nameof binding`, `nameof
binding.key`, and `nameof binding[key]`, where it returns the expression at
that parameter position as the "name", with a more convoluted fallback
algorithm to handle destructuring and local references sensibly. (It should
only consider parse-time data, and it should always strip whitespace and
unnecessary parentheses to keep it on a single line.) The required stack
space for this is just a single object pointer, and it's not like you can
do weird things with `eval` with it.
For security, there is the concern of unexpected passing of data through
parameters (think: `getSensitive("sensitive string")` as a parameter), but
this can be addressed on the minifier side via a directive and on the
language side by blocking all name sharing cross-realm (making them just
canonical strings derived from values instead).
On Fri, Jun 14, 2019 at 09:05 Stas Berkov wrote:
> Can we revisit this issue?
>
>
> In C# there is `nameof`, in Swift you can do the same by calling
>
> ```
>
> let keyPath = \Person.mother.firstName
>
> NSPredicate(format: "%K == %@", keyPath, "Andrew")
>
> ```
>
> Let's introduce `nameof` in ES, please.
>
>
> Devs from TypeScript don't want to introduce this feature in TypeScript
> unless it is available in ES (
> https://github.com/microsoft/TypeScript/issues/1579 )
>
> This feature is eagarly being asked by TypeScript community.
>
>
> I understand there are couple issues related to `nameof` feature in ES.
> They are: minification and what to do if user already has `nameof` function.
>
>
> Minification.
>
> 1. If your code to be minimized be prepared that variable names will also
> change.
>
> 2. (just a possibility) Minimizer can have option to replace
> `nameof(someVar)` with result of `nameof` function.
>
>
>
> What if user already has `nameof` function.
>
> 1. To maintain status quo we can user `nameof` function having priority
> over newly introduced language feature.
>
> 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns
> "userName" string)
> ___
> es-discuss mailing list
> es-discuss@mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
--
-
Isiah Meadows
cont...@isiahmeadows.com
www.isiahmeadows.com
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Re: Re: What do you think about a C# 6 like nameof() expression for
> What should occur where the code is
It would be "y" in all 3 places.
> ... is a proposal for _more_ than only getting the _name_ of an _declared_
> and _initialized_ variable?
It is a proposal for getting the name of a _declared_ variable. Whether it is
_initialized_ does not matter.
> Should a ```RefefenceError``` _not_ be thrown simple because ```nameof``` is
> used?
No, an error is not thrown. ECMAScript is much more nuanced. Block scoped
variables from 'let' or 'const' exist and can be *referenced* (via closure or
export, currently) anywhere within the same block scope, even before they are
initialized. Until they have been *initialized* (the line of code contain the
declaration has been reached and evaluated), they exist in a "Temporal Dead
Zone" (TDZ). Attempting to *dereference* them (i.e. access or store a value)
while in this TDZ is what results in the ReferenceError.
At no point does the `nameof` operator *dereference* the variable, so no error
need be thrown.
From: guest271314
Sent: Saturday, June 15, 4:29 PM
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
To: Ron Buckton
Cc: es-discuss@mozilla.org
What should occur where the code is
```
const x = nameof y
await new Promise(resolve => setTimeout(resolve, 10)); // should x be "y"
here?
await new Promise(resolve => setTimeout(resolve, 20)); // should x be "y"
here?
await Promise.all([new Promise(resolve => setTimeout(resolve, 30)),
...doStuff()]); // should x be "y" here?
const y = 1;
```
?
The immediately invoked arrow function example (where a ```RefeferenceError```
is thrown) appears to demonstrate that to output the expected result of
```nameof``` within the context of the code example
```
const x = nameof y
const y = 1;
```
is a proposal for _more_ than only getting the _name_ of an _declared_ and
_initialized_ variable?
Should a ```RefefenceError``` _not_ be thrown simple because ```nameof``` is
used?
On Sat, Jun 15, 2019 at 11:16 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
```
const x = nameof y
const y = 1;
```
`x` would have the value “y”. It would not matter if `y` were initialized or
had yet been reached during execution. It does not deviate from the purpose of
`let` or `const`, because you are not accessing the value of the identifier.
Also consider that this is legal ECMAScript in a module:
```
export { y }
const y = 1;
```
The binding for `y` exists within the same block scope, it just has not yet
been initialized. Exporting it via `export { y }`, closing over it via `() =>
y`, or accessing it via `nameof y` would all be the same. In all three cases
you are accessing the *binding* of `y`, not the *value* of `y`. Even in the `()
=> y` case, you don’t access the *value* of `y` until you execute the function.
From: guest271314 mailto:guest271...@gmail.com>>
Sent: Saturday, June 15, 2019 3:57 PM
To: Ron Buckton mailto:ron.buck...@microsoft.com>>
Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org>
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
> Sorry, I meant to say “not entirely correct”.
You have not yet confirmed if in fact the expected output is referencing a
variable declared using ```const``` on the current line _before_ initialization
_on the next line_.
That example appears to deviate from the purpose and usage of ```const```,
beyond the scope of ```nameof```, and if were implemented, a
```ReferenceError``` should _not_ be thrown when a ```const``` variable that
has yet to be initialized _on the next line_ is referred to _on the current
line_?
Aside from that example, the code which essentially already implements
```nameof``` should be able to be found in the code which implements
```ReferenceError``` relevant to ```const```.
On Sat, Jun 15, 2019 at 10:47 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
Sorry, I meant to say “not entirely correct”.
From: Ron Buckton
Sent: Saturday, June 15, 2019 3:03 PM
To: guest271314 mailto:guest271...@gmail.com>>
Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org>
Subject: RE: Re: What do you think about a C# 6 like nameof() expression for
> At that point in the example code the identifer ```y``` does not exist.
That is not entirely incorrect. The identifier `y` exists, but its binding has
not been initialized, otherwise you couldn’t refer to y in this case:
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Re: Re: What do you think about a C# 6 like nameof() expression for
What should occur where the code is
```
const x = nameof y
await new Promise(resolve => setTimeout(resolve, 10)); // should x be
"y" here?
await new Promise(resolve => setTimeout(resolve, 20)); // should x be
"y" here?
await Promise.all([new Promise(resolve => setTimeout(resolve, 30)),
...doStuff()]); // should x be "y" here?
const y = 1;
```
?
The immediately invoked arrow function example (where a
```RefeferenceError``` is thrown) appears to demonstrate that to output the
expected result of ```nameof``` within the context of the code example
```
const x = nameof y
const y = 1;
```
is a proposal for _more_ than only getting the _name_ of an _declared_ and
_initialized_ variable?
Should a ```RefefenceError``` _not_ be thrown simple because ```nameof```
is used?
On Sat, Jun 15, 2019 at 11:16 PM Ron Buckton
wrote:
> ```
>
> const x = nameof y
>
> const y = 1;
>
> ```
>
>
>
> `x` would have the value “y”. It would not matter if `y` were initialized
> or had yet been reached during execution. It does not deviate from the
> purpose of `let` or `const`, because you are not accessing the *value* of
> the identifier.
>
>
>
> Also consider that this is legal ECMAScript in a module:
>
>
>
> ```
>
> export { y }
>
> const y = 1;
>
> ```
>
>
>
> The binding for `y` exists within the same block scope, it just has not
> yet been initialized. Exporting it via `export { y }`, closing over it via
> `() => y`, or accessing it via `nameof y` would all be the same. In all
> three cases you are accessing the **binding** of `y`, not the **value**
> of `y`. Even in the `() => y` case, you don’t access the **value** of `y`
> until you execute the function.
>
>
>
> *From:* guest271314
> *Sent:* Saturday, June 15, 2019 3:57 PM
> *To:* Ron Buckton
> *Cc:* es-discuss@mozilla.org
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> > Sorry, I meant to say “not entirely correct”.
>
>
>
> You have not yet confirmed if in fact the expected output is referencing a
> variable declared using ```const``` on the current line _before_
> initialization _on the next line_.
>
>
>
> That example appears to deviate from the purpose and usage of ```const```,
> beyond the scope of ```nameof```, and if were implemented, a
> ```ReferenceError``` should _not_ be thrown when a ```const``` variable
> that has yet to be initialized _on the next line_ is referred to _on the
> current line_?
>
>
>
> Aside from that example, the code which essentially already implements
> ```nameof``` should be able to be found in the code which implements
> ```ReferenceError``` relevant to ```const```.
>
>
>
> On Sat, Jun 15, 2019 at 10:47 PM Ron Buckton
> wrote:
>
> Sorry, I meant to say “not entirely correct”.
>
>
>
> *From:* Ron Buckton
> *Sent:* Saturday, June 15, 2019 3:03 PM
> *To:* guest271314
> *Cc:* es-discuss@mozilla.org
> *Subject:* RE: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> > At that point in the example code the identifer ```y``` does not exist.
>
>
>
> That is not entirely incorrect. The identifier `y` exists, but its binding
> has not been initialized, otherwise you couldn’t refer to y in this case:
>
>
>
>
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
> Sorry, I meant to say “not entirely correct”. You have not yet confirmed if in fact the expected output is referencing a variable declared using ```const``` on the current line _before_ initialization _on the next line_. That example appears to deviate from the purpose and usage of ```const```, beyond the scope of ```nameof```, and if were implemented, a ```ReferenceError``` should _not_ be thrown when a ```const``` variable that has yet to be initialized _on the next line_ is referred to _on the current line_? Aside from that example, the code which essentially already implements ```nameof``` should be able to be found in the code which implements ```ReferenceError``` relevant to ```const```. On Sat, Jun 15, 2019 at 10:47 PM Ron Buckton wrote: > Sorry, I meant to say “not entirely correct”. > > > > *From:* Ron Buckton > *Sent:* Saturday, June 15, 2019 3:03 PM > *To:* guest271314 > *Cc:* es-discuss@mozilla.org > *Subject:* RE: Re: What do you think about a C# 6 like nameof() > expression for > > > > > At that point in the example code the identifer ```y``` does not exist. > > > > That is not entirely incorrect. The identifier `y` exists, but its binding > has not been initialized, otherwise you couldn’t refer to y in this case: > > > ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
```
const f = () => y;
let y = 1;
```
is different (dissimilar) code than the original reference example code.
> I don’t disagree that there are “alternative approaches” to ‘nameof’ for
many cases, but they all incur overhead.
Given that a ```ReferenceError``` is thrown when attempting to reference a
variable declared using ```const``` where the ```message``` property
includes the name of the variable, either the specification and, or the
implementers are already getting the name of the idetifier as a string and
outputing the described requirement of ```nameof``` in a similar context.
Thus, the code already exists. It would appear it is now a matter of
locating that source code in browser implementations and abstracting the
process to a ```nameof``` function or operator.
Have you looked into the source code of browsers that implement ```const```
to determine the issues, if any, as to utilizing the existiing
implementation(s) of ```ReferenceError``` to facilitate ```nameof``` while
avoiding incurring the described "overhead" of using workarounds to achieve
the same output?
On Sat, Jun 15, 2019 at 10:03 PM Ron Buckton
wrote:
> > At that point in the example code the identifer ```y``` does not exist.
>
>
>
> That is not entirely incorrect. The identifier `y` exists, but its binding
> has not been initialized, otherwise you couldn’t refer to y in this case:
>
>
>
> ```
>
> const f = () => y;
>
> let y = 1;
>
> ```
>
>
>
> > That fact can be utilized for an alternative approach to meet
> requirement of "Case 1. Function guard.".
>
>
>
> I don’t disagree that there are “alternative approaches” to ‘nameof’ for
> many cases, but they all incur overhead.
>
>
>
> At the end of the day, ‘nameof’ is a convenience feature that provides an
> incremental “quality of life” improvement, much like shorthand property
> assignments were a convenience feature (i.e. how hard is it to write `{
> foo: foo }`). It’s not something that would be as much of a game changer to
> the language as async/await or yield were, but it would be a fairly easily
> spec’d and nice-to-have capability.
>
>
>
> *From:* guest271314
> *Sent:* Saturday, June 15, 2019 2:50 PM
> *To:* Ron Buckton
> *Cc:* es-discuss@mozilla.org
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> > It doesn’t matter what the *value* of ‘y’ is, just what the lexical
> name of `y` is. `nameof` wouldn’t refer to `y` as an expression, its just
> pointing to the identifier.
>
>
>
> Was not referring to the _value_ of ```y```. At that point in the example
> code the identifer ```y``` does not exist. That is, unless there was an
> expected presumption that ```y``` was defined globally prior to the
> ```const y = 1;``` declaration at the next line. Even then a variable
> declared using ```const``` cannot be referenced before "lexical
> declaration" or "initialization". That fact can be utilized for an
> alternative approach to meet requirement of "Case 1. Function guard.".
> Tested at Chromium 76 and Firefox 69. Have not used MS browser (or
> browserstack) in some time. Have not tried the code at Safari either,
> though the code is capable of adjustment for any JavaScript environment
> which throws a ```ReferenceError``` under the same case
>
>
>
> ```
>
> function func1(param1, param2, param3, userName, param4, param5) {
> if (userName === undefined) {
> try {
> // throws ReferenceError
> // Firefox 69: ReferenceError: "can't access lexical declaration
> `userName' before initialization"
> // Chromium 76: ReferenceError: Cannot access 'userName' before
> initialization
> const userName = userName;
> } catch (e) {
> // match identifier at Firefox, Chromium ReferenceError message
> // adjust RegExp for IE/Edge, Safari, etc.
> const nameof = e.message.match(/(?!`|')[^\s]+(?=')/g).pop();
> throw new Error(`"Argument cannot be null: ${nameof}"`);
> }
> } else {
> // do stuff
> console.log(userName);
> }
> }
>
> try {
> func1(1, 2, 3); // throws error
> } catch (e) {
> console.error(e); // get name of variable identifier
> }
>
> try {
> func1(1, 2, 3, 4); // logs userName at console
> } catch (e) {
> console.error(e); // should not be reached
> }
>
> ```
>
>
>
> On Sat, Jun 15, 2019 at 9:37 PM Ron Buckton
> wrote:
>
> It doesn’t matter what the *value* of ‘y’ is, just what the lexical name
> of `y` is. `nameof` wouldn’t refer to `y` as an expression, its just
> pointing to the identifier.
>
>
>
> *From:* guest2713
RE: Re: What do you think about a C# 6 like nameof() expression for
> At that point in the example code the identifer ```y``` does not exist.
That is not entirely incorrect. The identifier `y` exists, but its binding has
not been initialized, otherwise you couldn’t refer to y in this case:
```
const f = () => y;
let y = 1;
```
> That fact can be utilized for an alternative approach to meet requirement of
> "Case 1. Function guard.".
I don’t disagree that there are “alternative approaches” to ‘nameof’ for many
cases, but they all incur overhead.
At the end of the day, ‘nameof’ is a convenience feature that provides an
incremental “quality of life” improvement, much like shorthand property
assignments were a convenience feature (i.e. how hard is it to write `{ foo:
foo }`). It’s not something that would be as much of a game changer to the
language as async/await or yield were, but it would be a fairly easily spec’d
and nice-to-have capability.
From: guest271314
Sent: Saturday, June 15, 2019 2:50 PM
To: Ron Buckton
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
> It doesn’t matter what the value of ‘y’ is, just what the lexical name of `y`
> is. `nameof` wouldn’t refer to `y` as an expression, its just pointing to the
> identifier.
Was not referring to the _value_ of ```y```. At that point in the example code
the identifer ```y``` does not exist. That is, unless there was an expected
presumption that ```y``` was defined globally prior to the ```const y = 1;```
declaration at the next line. Even then a variable declared using ```const```
cannot be referenced before "lexical declaration" or "initialization". That
fact can be utilized for an alternative approach to meet requirement of "Case
1. Function guard.". Tested at Chromium 76 and Firefox 69. Have not used MS
browser (or browserstack) in some time. Have not tried the code at Safari
either, though the code is capable of adjustment for any JavaScript environment
which throws a ```ReferenceError``` under the same case
```
function func1(param1, param2, param3, userName, param4, param5) {
if (userName === undefined) {
try {
// throws ReferenceError
// Firefox 69: ReferenceError: "can't access lexical declaration
`userName' before initialization"
// Chromium 76: ReferenceError: Cannot access 'userName' before
initialization
const userName = userName;
} catch (e) {
// match identifier at Firefox, Chromium ReferenceError message
// adjust RegExp for IE/Edge, Safari, etc.
const nameof = e.message.match(/(?!`|')[^\s]+(?=')/g).pop();
throw new Error(`"Argument cannot be null: ${nameof}"`);
}
} else {
// do stuff
console.log(userName);
}
}
try {
func1(1, 2, 3); // throws error
} catch (e) {
console.error(e); // get name of variable identifier
}
try {
func1(1, 2, 3, 4); // logs userName at console
} catch (e) {
console.error(e); // should not be reached
}
```
On Sat, Jun 15, 2019 at 9:37 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
It doesn’t matter what the value of ‘y’ is, just what the lexical name of `y`
is. `nameof` wouldn’t refer to `y` as an expression, its just pointing to the
identifier.
From: guest271314 mailto:guest271...@gmail.com>>
Sent: Friday, June 14, 2019 10:03 PM
To: Ron Buckton mailto:ron.buck...@microsoft.com>>
Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org>
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
> I’m not sure I understand what you mean by “false-positive” in this instance.
Was referring to
const x = nameof y; // "y"
const y = 1;
Where ```y``` is ```undefined``` an error is not expected to be thrown? Is
```y``` declared globally, using ```const``` or ```let```, or not at all? The
use case described by OP
function func1(param1, param2, param3, userName, param4, param5) {
if (userName == undefined) {
throw new ArgumentNullError(nameof userName); // `ArgumentNullError`
is a custom error, derived from `Error`, composes error message like
"Argument cannot be null: userName".
}
checks if ```userName``` was ```undefined``` before using ```nameof```. If
error checking is a substantial portion of the proposal, why should an error
(```y``` being ```undefined``` though referenced) be ignored when referencing
an undefined identifier though concentrate on coercing a name from a different
potentially undefined property?
Consider this case:
```
const someObject = { value: 1 };
function setValue(value /*1*/) {
if (typeof value /*2*/ !== "number") throw new TypeError(`Number expected:
${nameof value /*3*/}`);
someObject["value" /*4*/] = value /*5*/;
}
```
If you rename the parameter `value` of the function `setValue` in an editor
with a rename refactoring, you want to rename the symbols at 1, 2, 3, and 5,
but
Re: Re: What do you think about a C# 6 like nameof() expression for
> It doesn’t matter what the *value* of ‘y’ is, just what the lexical name
of `y` is. `nameof` wouldn’t refer to `y` as an expression, its just
pointing to the identifier.
Was not referring to the _value_ of ```y```. At that point in the example
code the identifer ```y``` does not exist. That is, unless there was an
expected presumption that ```y``` was defined globally prior to the
```const y = 1;``` declaration at the next line. Even then a variable
declared using ```const``` cannot be referenced before "lexical
declaration" or "initialization". That fact can be utilized for an
alternative approach to meet requirement of "Case 1. Function guard.".
Tested at Chromium 76 and Firefox 69. Have not used MS browser (or
browserstack) in some time. Have not tried the code at Safari either,
though the code is capable of adjustment for any JavaScript environment
which throws a ```ReferenceError``` under the same case
```
function func1(param1, param2, param3, userName, param4, param5) {
if (userName === undefined) {
try {
// throws ReferenceError
// Firefox 69: ReferenceError: "can't access lexical declaration
`userName' before initialization"
// Chromium 76: ReferenceError: Cannot access 'userName' before
initialization
const userName = userName;
} catch (e) {
// match identifier at Firefox, Chromium ReferenceError message
// adjust RegExp for IE/Edge, Safari, etc.
const nameof = e.message.match(/(?!`|')[^\s]+(?=')/g).pop();
throw new Error(`"Argument cannot be null: ${nameof}"`);
}
} else {
// do stuff
console.log(userName);
}
}
try {
func1(1, 2, 3); // throws error
} catch (e) {
console.error(e); // get name of variable identifier
}
try {
func1(1, 2, 3, 4); // logs userName at console
} catch (e) {
console.error(e); // should not be reached
}
```
On Sat, Jun 15, 2019 at 9:37 PM Ron Buckton
wrote:
> It doesn’t matter what the *value* of ‘y’ is, just what the lexical name
> of `y` is. `nameof` wouldn’t refer to `y` as an expression, its just
> pointing to the identifier.
>
>
>
> *From:* guest271314
> *Sent:* Friday, June 14, 2019 10:03 PM
> *To:* Ron Buckton
> *Cc:* es-discuss@mozilla.org
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> > I’m not sure I understand what you mean by “false-positive” in this
> instance.
>
>
>
> Was referring to
>
>
>
> const x = nameof y; // "y"
>
> const y = 1;
>
>
>
> Where ```y``` is ```undefined``` an error is not expected to be thrown? Is
> ```y``` declared globally, using ```const``` or ```let```, or not at all?
> The use case described by OP
>
>
>
> function func1(param1, param2, param3, userName, param4, param5) {
>
>if (userName == undefined) {
>
>throw new ArgumentNullError(nameof userName); // `ArgumentNullError`
>
> is a custom error, derived from `Error`, composes error message like
>
> "Argument cannot be null: userName".
>
>}
>
> checks if ```userName``` was ```undefined``` before using ```nameof```.
> If error checking is a substantial portion of the proposal, why should an
> error (```y``` being ```undefined``` though referenced) be ignored when
> referencing an undefined identifier though concentrate on coercing a name
> from a different potentially undefined property?
>
>
>
> Consider this case:
> ```
> const someObject = { value: 1 };
> function setValue(value /*1*/) {
> if (typeof value /*2*/ !== "number") throw new TypeError(`Number
> expected: ${nameof value /*3*/}`);
> someObject["value" /*4*/] = value /*5*/;
> }
> ```
>
> If you rename the parameter `value` of the function `setValue` in an
> editor with a rename refactoring, you want to rename the symbols at 1, 2,
> 3, and 5, but not the string at 4.
>
>
>
> Not gathering the purpose or value of ```nameof``` usage in that case. If
> the value is not a "number" then why does the value or name matter?
>
>
>
> Since the primary use case appears to be an editor environment, why cannot
> the editor be programmed to recognize the custom JavaScript ```nameof
> function or operator? Then it would not matter if this board concurred with
> the ```nameof``` functionality or not. Both CLI and GUI editors (and
> JavaScript) are generally extensible. FWIW, some time ago incorporated
> features into gedit for HTML templates; should be a similar process to
> create custom scripts for the various editor environments where users rely
> on such programs for code composition; now simply write the code by hand
> and test in different environments, without taking the time to customize or
> rely on an editor - t
RE: Re: What do you think about a C# 6 like nameof() expression for
It doesn’t matter what the value of ‘y’ is, just what the lexical name of `y`
is. `nameof` wouldn’t refer to `y` as an expression, its just pointing to the
identifier.
From: guest271314
Sent: Friday, June 14, 2019 10:03 PM
To: Ron Buckton
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
> I’m not sure I understand what you mean by “false-positive” in this instance.
Was referring to
const x = nameof y; // "y"
const y = 1;
Where ```y``` is ```undefined``` an error is not expected to be thrown? Is
```y``` declared globally, using ```const``` or ```let```, or not at all? The
use case described by OP
function func1(param1, param2, param3, userName, param4, param5) {
if (userName == undefined) {
throw new ArgumentNullError(nameof userName); // `ArgumentNullError`
is a custom error, derived from `Error`, composes error message like
"Argument cannot be null: userName".
}
checks if ```userName``` was ```undefined``` before using ```nameof```. If
error checking is a substantial portion of the proposal, why should an error
(```y``` being ```undefined``` though referenced) be ignored when referencing
an undefined identifier though concentrate on coercing a name from a different
potentially undefined property?
Consider this case:
```
const someObject = { value: 1 };
function setValue(value /*1*/) {
if (typeof value /*2*/ !== "number") throw new TypeError(`Number expected:
${nameof value /*3*/}`);
someObject["value" /*4*/] = value /*5*/;
}
```
If you rename the parameter `value` of the function `setValue` in an editor
with a rename refactoring, you want to rename the symbols at 1, 2, 3, and 5,
but not the string at 4.
Not gathering the purpose or value of ```nameof``` usage in that case. If the
value is not a "number" then why does the value or name matter?
Since the primary use case appears to be an editor environment, why cannot the
editor be programmed to recognize the custom JavaScript ```nameof function
or operator? Then it would not matter if this board concurred with the
```nameof``` functionality or not. Both CLI and GUI editors (and JavaScript)
are generally extensible. FWIW, some time ago incorporated features into gedit
for HTML templates; should be a similar process to create custom scripts for
the various editor environments where users rely on such programs for code
composition; now simply write the code by hand and test in different
environments, without taking the time to customize or rely on an editor - take
the time to test the code where the code will actually be run where errors, if
any, can be evaluated in the context in which a specific output is expected. To
each their own. What needs to be implemented outside of what the users which
advocate for ```nameof``` cannot implement themselves?
As mentioned earlier do not rely on "an editor with name refactoring" to
compose code. The code has to be tested (outside of the editor environments)
anyway. Test the code itself, here, not the editor.
On Fri, Jun 14, 2019 at 9:49 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
I’m not sure I understand what you mean by “false-positive” in this instance.
Consider this case:
```
const someObject = { value: 1 };
function setValue(value /*1*/) {
if (typeof value /*2*/ !== "number") throw new TypeError(`Number expected:
${nameof value /*3*/}`);
someObject["value" /*4*/] = value /*5*/;
}
```
If you rename the parameter `value` of the function `setValue` in an editor
with a rename refactoring, you want to rename the symbols at 1, 2, 3, and 5,
but not the string at 4.
Ron
From: guest271314 mailto:guest271...@gmail.com>>
Sent: Friday, June 14, 2019 2:43 PM
To: Ron Buckton mailto:ron.buck...@microsoft.com>>
Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org>
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
How is that behaviour related to the use cases presented by OP? Would such
behaviour not lead to false-positive relevant to the 2 use cases?
On Fri, Jun 14, 2019 at 9:36 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
> `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused
> why it'd be better to type `nameof foo` in code, rather than `'foo'` - if you
> change `foo` to `bar`, you have to change both of them anyways.
If you are using an editor that supports rename refactoring, its generally
easier to rename the symbol `foo` and have all references (including `nameof
foo`) be updated. You cannot safely automatically rename `'foo'` to `'bar'`
since an editor or language service cannot guarantee that by the string `'foo'`
you meant “the text of the identifier `foo`”.
From: es-discuss
mailto:es-discuss-boun...@mozilla.org>> On
Behalf Of Jordan Harband
Sent: Friday, June 14, 201
Re: Re: What do you think about a C# 6 like nameof() expression for
> I’m not sure I understand what you mean by “false-positive” in this
instance.
Was referring to
const x = nameof y; // "y"
const y = 1;
Where ```y``` is ```undefined``` an error is not expected to be thrown? Is
```y``` declared globally, using ```const``` or ```let```, or not at all?
The use case described by OP
function func1(param1, param2, param3, userName, param4, param5) {
if (userName == undefined) {
throw new ArgumentNullError(nameof userName); // `ArgumentNullError`
is a custom error, derived from `Error`, composes error message like
"Argument cannot be null: userName".
}
checks if ```userName``` was ```undefined``` before using ```nameof```. If
error checking is a substantial portion of the proposal, why should an
error (```y``` being ```undefined``` though referenced) be ignored when
referencing an undefined identifier though concentrate on coercing a name
from a different potentially undefined property?
Consider this case:
> ```
> const someObject = { value: 1 };
> function setValue(value /*1*/) {
> if (typeof value /*2*/ !== "number") throw new TypeError(`Number
> expected: ${nameof value /*3*/}`);
> someObject["value" /*4*/] = value /*5*/;
> }
> ```
If you rename the parameter `value` of the function `setValue` in an editor
> with a rename refactoring, you want to rename the symbols at 1, 2, 3, and
> 5, but not the string at 4.
Not gathering the purpose or value of ```nameof``` usage in that case. If
the value is not a "number" then why does the value or name matter?
Since the primary use case appears to be an editor environment, why cannot
the editor be programmed to recognize the custom JavaScript ```nameof
function or operator? Then it would not matter if this board concurred with
the ```nameof``` functionality or not. Both CLI and GUI editors (and
JavaScript) are generally extensible. FWIW, some time ago incorporated
features into gedit for HTML templates; should be a similar process to
create custom scripts for the various editor environments where users rely
on such programs for code composition; now simply write the code by hand
and test in different environments, without taking the time to customize or
rely on an editor - take the time to test the code where the code will
actually be run where errors, if any, can be evaluated in the context in
which a specific output is expected. To each their own. What needs to be
implemented outside of what the users which advocate for ```nameof```
cannot implement themselves?
As mentioned earlier do not rely on "an editor with name refactoring" to
compose code. The code has to be tested (outside of the editor
environments) anyway. Test the code itself, here, not the editor.
On Fri, Jun 14, 2019 at 9:49 PM Ron Buckton
wrote:
> I’m not sure I understand what you mean by “false-positive” in this
> instance.
>
>
>
> Consider this case:
>
>
>
> ```
>
> const someObject = { value: 1 };
>
> function setValue(value /*1*/) {
>
> if (typeof value /*2*/ !== "number") throw new TypeError(`Number
> expected: ${nameof value /*3*/}`);
>
> someObject["value" /*4*/] = value /*5*/;
> }
>
> ```
>
>
>
> If you rename the parameter `value` of the function `setValue` in an
> editor with a rename refactoring, you want to rename the symbols at 1, 2,
> 3, and 5, but not the string at 4.
>
>
>
> Ron
>
>
>
> *From:* guest271314
> *Sent:* Friday, June 14, 2019 2:43 PM
> *To:* Ron Buckton
> *Cc:* es-discuss@mozilla.org
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> How is that behaviour related to the use cases presented by OP? Would such
> behaviour not lead to false-positive relevant to the 2 use cases?
>
>
>
> On Fri, Jun 14, 2019 at 9:36 PM Ron Buckton
> wrote:
>
> > `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit
> confused why it'd be better to type `nameof foo` in code, rather than
> `'foo'` - if you change `foo` to `bar`, you have to change both of them
> anyways.
>
>
>
> If you are using an editor that supports rename refactoring, its generally
> easier to rename the symbol `foo` and have all references (including
> `nameof foo`) be updated. You cannot safely automatically rename `'foo'` to
> `'bar'` since an editor or language service cannot guarantee that by the
> string `'foo'` you meant “the text of the identifier `foo`”.
>
>
>
> *From:* es-discuss *On Behalf Of *Jordan
> Harband
> *Sent:* Friday, June 14, 2019 2:29 PM
> *To:* guest271314
> *Cc:* es-discuss
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> `nameof whatever` → `Object.keys({ whatever })[0]`, but
RE: Re: What do you think about a C# 6 like nameof() expression for
I’m not sure I understand what you mean by “false-positive” in this instance.
Consider this case:
```
const someObject = { value: 1 };
function setValue(value /*1*/) {
if (typeof value /*2*/ !== "number") throw new TypeError(`Number expected:
${nameof value /*3*/}`);
someObject["value" /*4*/] = value /*5*/;
}
```
If you rename the parameter `value` of the function `setValue` in an editor
with a rename refactoring, you want to rename the symbols at 1, 2, 3, and 5,
but not the string at 4.
Ron
From: guest271314
Sent: Friday, June 14, 2019 2:43 PM
To: Ron Buckton
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
How is that behaviour related to the use cases presented by OP? Would such
behaviour not lead to false-positive relevant to the 2 use cases?
On Fri, Jun 14, 2019 at 9:36 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
> `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused
> why it'd be better to type `nameof foo` in code, rather than `'foo'` - if you
> change `foo` to `bar`, you have to change both of them anyways.
If you are using an editor that supports rename refactoring, its generally
easier to rename the symbol `foo` and have all references (including `nameof
foo`) be updated. You cannot safely automatically rename `'foo'` to `'bar'`
since an editor or language service cannot guarantee that by the string `'foo'`
you meant “the text of the identifier `foo`”.
From: es-discuss
mailto:es-discuss-boun...@mozilla.org>> On
Behalf Of Jordan Harband
Sent: Friday, June 14, 2019 2:29 PM
To: guest271314 mailto:guest271...@gmail.com>>
Cc: es-discuss mailto:es-discuss@mozilla.org>>
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
`nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused why
it'd be better to type `nameof foo` in code, rather than `'foo'` - if you
change `foo` to `bar`, you have to change both of them anyways.
On Fri, Jun 14, 2019 at 1:31 PM guest271314
mailto:guest271...@gmail.com>> wrote:
Am neither for nor against the proposal. Do not entertain "like"s or "dislike"s
in any field of endeavor. Am certainly not in a position to prohibit anything
relevant JavaScript. Do what thou wilt shall be the whole of the Law.
Have yet to view a case where code will be "broken" by ```nameof``` not being a
JavaScript feature. "robustness", as already mentioned, is a subjective
adjective that is not capable of being objectively evaluated as to code itself.
That description is based on preference or choice.
In lieu of the proposal being specificed, use the posted code example of
```Object.keys()``` that "works".
```
function func1({userName = void 0} = {}) {
console.assert(userName !== undefined, [{userName}, 'property needs to be
defined'])
}
```
provides a direct indication that the property value is required to be defined.
Note that the example code posted thus far does not first check if
```options``` is passed at all, for which ```nameof``` will not provide any
asssitance.
Usually try to meet requirement by means already available in FOSS browsers.
Have no interest in TypeScript or using an IDE.
FWIW, have no objection to the proposal.
On Fri, Jun 14, 2019 at 7:53 PM Stas Berkov
mailto:stas.ber...@gmail.com>> wrote:
guest271314, what is you point against `nameof` feature?
If you don't like it - don't use it. Why prohibit this feature for
those who find it beneficial?
I see `nameof` beneficial in following cases
Case 1. Function guard.
```
function func1(options) {
...
if (options.userName == undefined) {
throw new ParamNullError(nameof options.userName); //
`ParamNullError` is a custom error, derived from `Error`, composes
error message like "Parameter cannot be null: userName".
// `Object.keys({options.userName})[0]` will not work here
}
}
```
Case 2. Accessing property extended info
Those ES functions that accept field name as string.
e.g.
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
```
vs
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
object1.property1);
// `Object.keys({options1.property1})[0]` will not work here
```
2nd variant (proposed) has more chances not to be broken during
refactoring (robustness).
It would make devs who use IDE more productive and make their life
easier. Why not give them such possiblity and make them happy?
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Re: Re: What do you think about a C# 6 like nameof() expression for
Fri, 14 jun 2019 - 18:29, Jordan Harband wrote:
>
> `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused
> why it'd be better to type `nameof foo` in code, rather than `'foo'` - if you
> change `foo` to `bar`, you have to change both of them anyways.
>
Exactly, if you already have the name of the property beforehand in
design time why not write it as a string literal
Again, the only justifiable use case is refactoring tools, but even
today that can be arranged with static code analysis
You can safe guard a string literal to be a property of a type in
Typescript with a bit of handwork
``` ts
interface Options {
userName?: string;
}
// If you change the property in the interface without changing here, Typescript
// will raise a error informing that 'userName' is not a valid key of Options
const userNameKey: keyof Options = 'userName';
if (options.userName === undefined) {
throw new ParamNullError(userNameKey);
}
```
--
Atenciosamente,
Augusto Borges de Moura
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Re: Re: What do you think about a C# 6 like nameof() expression for
How is that behaviour related to the use cases presented by OP? Would such
behaviour not lead to false-positive relevant to the 2 use cases?
On Fri, Jun 14, 2019 at 9:36 PM Ron Buckton
wrote:
> > `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit
> confused why it'd be better to type `nameof foo` in code, rather than
> `'foo'` - if you change `foo` to `bar`, you have to change both of them
> anyways.
>
>
>
> If you are using an editor that supports rename refactoring, its generally
> easier to rename the symbol `foo` and have all references (including
> `nameof foo`) be updated. You cannot safely automatically rename `'foo'` to
> `'bar'` since an editor or language service cannot guarantee that by the
> string `'foo'` you meant “the text of the identifier `foo`”.
>
>
>
> *From:* es-discuss * On Behalf Of *Jordan
> Harband
> *Sent:* Friday, June 14, 2019 2:29 PM
> *To:* guest271314
> *Cc:* es-discuss
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
>
>
> `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused
> why it'd be better to type `nameof foo` in code, rather than `'foo'` - if
> you change `foo` to `bar`, you have to change both of them anyways.
>
>
>
> On Fri, Jun 14, 2019 at 1:31 PM guest271314 wrote:
>
> Am neither for nor against the proposal. Do not entertain "like"s or
> "dislike"s in any field of endeavor. Am certainly not in a position to
> prohibit anything relevant JavaScript. Do what thou wilt shall be the whole
> of the Law.
>
> Have yet to view a case where code will be "broken" by ```nameof``` not
> being a JavaScript feature. "robustness", as already mentioned, is a
> subjective adjective that is not capable of being objectively evaluated as
> to code itself. That description is based on preference or choice.
>
>
>
> In lieu of the proposal being specificed, use the posted code example of
> ```Object.keys()``` that "works".
>
>
>
> ```
>
> function func1({userName = void 0} = {}) {
> console.assert(userName !== undefined, [{userName}, 'property needs to
> be defined'])
> }
>
> ```
>
>
>
> provides a direct indication that the property value is required to be
> defined. Note that the example code posted thus far does not first check if
> ```options``` is passed at all, for which ```nameof``` will not provide any
> asssitance.
>
>
>
> Usually try to meet requirement by means already available in FOSS
> browsers. Have no interest in TypeScript or using an IDE.
>
>
>
> FWIW, have no objection to the proposal.
>
>
>
> On Fri, Jun 14, 2019 at 7:53 PM Stas Berkov wrote:
>
> guest271314, what is you point against `nameof` feature?
>
> If you don't like it - don't use it. Why prohibit this feature for
> those who find it beneficial?
>
> I see `nameof` beneficial in following cases
>
> Case 1. Function guard.
> ```
> function func1(options) {
> ...
>if (options.userName == undefined) {
>throw new ParamNullError(nameof options.userName); //
> `ParamNullError` is a custom error, derived from `Error`, composes
> error message like "Parameter cannot be null: userName".
> // `Object.keys({options.userName})[0]` will not work here
>}
> }
> ```
>
> Case 2. Accessing property extended info
> Those ES functions that accept field name as string.
> e.g.
> ```
> const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
> ```
> vs
> ```
> const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
> object1.property1);
> // `Object.keys({options1.property1})[0]` will not work here
> ```
> 2nd variant (proposed) has more chances not to be broken during
> refactoring (robustness).
>
> It would make devs who use IDE more productive and make their life
> easier. Why not give them such possiblity and make them happy?
>
> ___
> es-discuss mailing list
> es-discuss@mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
> <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.mozilla.org%2Flistinfo%2Fes-discuss=02%7C01%7Cron.buckton%40microsoft.com%7C9fdfd117bd4346c8001b08d6f10f6d33%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636961445923877688=d5aVBUC9Aptqxm9l9bzlqzyKvKKJhVXg7RGosfnXN8M%3D=0>
>
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RE: Re: What do you think about a C# 6 like nameof() expression for
> `nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused
> why it'd be better to type `nameof foo` in code, rather than `'foo'` - if you
> change `foo` to `bar`, you have to change both of them anyways.
If you are using an editor that supports rename refactoring, its generally
easier to rename the symbol `foo` and have all references (including `nameof
foo`) be updated. You cannot safely automatically rename `'foo'` to `'bar'`
since an editor or language service cannot guarantee that by the string `'foo'`
you meant “the text of the identifier `foo`”.
From: es-discuss On Behalf Of Jordan Harband
Sent: Friday, June 14, 2019 2:29 PM
To: guest271314
Cc: es-discuss
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
`nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused why
it'd be better to type `nameof foo` in code, rather than `'foo'` - if you
change `foo` to `bar`, you have to change both of them anyways.
On Fri, Jun 14, 2019 at 1:31 PM guest271314
mailto:guest271...@gmail.com>> wrote:
Am neither for nor against the proposal. Do not entertain "like"s or "dislike"s
in any field of endeavor. Am certainly not in a position to prohibit anything
relevant JavaScript. Do what thou wilt shall be the whole of the Law.
Have yet to view a case where code will be "broken" by ```nameof``` not being a
JavaScript feature. "robustness", as already mentioned, is a subjective
adjective that is not capable of being objectively evaluated as to code itself.
That description is based on preference or choice.
In lieu of the proposal being specificed, use the posted code example of
```Object.keys()``` that "works".
```
function func1({userName = void 0} = {}) {
console.assert(userName !== undefined, [{userName}, 'property needs to be
defined'])
}
```
provides a direct indication that the property value is required to be defined.
Note that the example code posted thus far does not first check if
```options``` is passed at all, for which ```nameof``` will not provide any
asssitance.
Usually try to meet requirement by means already available in FOSS browsers.
Have no interest in TypeScript or using an IDE.
FWIW, have no objection to the proposal.
On Fri, Jun 14, 2019 at 7:53 PM Stas Berkov
mailto:stas.ber...@gmail.com>> wrote:
guest271314, what is you point against `nameof` feature?
If you don't like it - don't use it. Why prohibit this feature for
those who find it beneficial?
I see `nameof` beneficial in following cases
Case 1. Function guard.
```
function func1(options) {
...
if (options.userName == undefined) {
throw new ParamNullError(nameof options.userName); //
`ParamNullError` is a custom error, derived from `Error`, composes
error message like "Parameter cannot be null: userName".
// `Object.keys({options.userName})[0]` will not work here
}
}
```
Case 2. Accessing property extended info
Those ES functions that accept field name as string.
e.g.
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
```
vs
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
object1.property1);
// `Object.keys({options1.property1})[0]` will not work here
```
2nd variant (proposed) has more chances not to be broken during
refactoring (robustness).
It would make devs who use IDE more productive and make their life
easier. Why not give them such possiblity and make them happy?
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Re: Re: What do you think about a C# 6 like nameof() expression for
`nameof whatever` → `Object.keys({ whatever })[0]`, but I'm a bit confused
why it'd be better to type `nameof foo` in code, rather than `'foo'` - if
you change `foo` to `bar`, you have to change both of them anyways.
On Fri, Jun 14, 2019 at 1:31 PM guest271314 wrote:
> Am neither for nor against the proposal. Do not entertain "like"s or
> "dislike"s in any field of endeavor. Am certainly not in a position to
> prohibit anything relevant JavaScript. Do what thou wilt shall be the whole
> of the Law.
>
> Have yet to view a case where code will be "broken" by ```nameof``` not
> being a JavaScript feature. "robustness", as already mentioned, is a
> subjective adjective that is not capable of being objectively evaluated as
> to code itself. That description is based on preference or choice.
>
> In lieu of the proposal being specificed, use the posted code example of
> ```Object.keys()``` that "works".
>
> ```
> function func1({userName = void 0} = {}) {
> console.assert(userName !== undefined, [{userName}, 'property needs to
> be defined'])
> }
> ```
>
> provides a direct indication that the property value is required to be
> defined. Note that the example code posted thus far does not first check if
> ```options``` is passed at all, for which ```nameof``` will not provide any
> asssitance.
>
> Usually try to meet requirement by means already available in FOSS
> browsers. Have no interest in TypeScript or using an IDE.
>
> FWIW, have no objection to the proposal.
>
> On Fri, Jun 14, 2019 at 7:53 PM Stas Berkov wrote:
>
>> guest271314, what is you point against `nameof` feature?
>>
>> If you don't like it - don't use it. Why prohibit this feature for
>> those who find it beneficial?
>>
>> I see `nameof` beneficial in following cases
>>
>> Case 1. Function guard.
>> ```
>> function func1(options) {
>> ...
>>if (options.userName == undefined) {
>>throw new ParamNullError(nameof options.userName); //
>> `ParamNullError` is a custom error, derived from `Error`, composes
>> error message like "Parameter cannot be null: userName".
>> // `Object.keys({options.userName})[0]` will not work here
>>}
>> }
>> ```
>>
>> Case 2. Accessing property extended info
>> Those ES functions that accept field name as string.
>> e.g.
>> ```
>> const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
>> ```
>> vs
>> ```
>> const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
>> object1.property1);
>> // `Object.keys({options1.property1})[0]` will not work here
>> ```
>> 2nd variant (proposed) has more chances not to be broken during
>> refactoring (robustness).
>>
>> It would make devs who use IDE more productive and make their life
>> easier. Why not give them such possiblity and make them happy?
>>
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> https://mail.mozilla.org/listinfo/es-discuss
>
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RE: Re: What do you think about a C# 6 like nameof() expression for
> Interesting. ```y``` would be able to be evaluated before ```y``` is defined? I very explicitly stated that `nameof y` would *not* evaluate its operand. Evaluation of `nameof` would merely result in a string containing the name of the binding referenced by the operand. From: es-discuss On Behalf Of guest271314 Sent: Friday, June 14, 2019 12:09 PM To: Stas Berkov Cc: es-discuss@mozilla.org Subject: Re: Re: What do you think about a C# 6 like nameof() expression for > A module namespace isn’t an instance of Module, it’s a module namespace spec > object. If it has a name member, that is because the module you imported has > an exported binding called name. But what kind of thing it is isn’t what > matters. If ```Object.getOwnPropertyDescriptors(ns)``` is used within ```
Re: Re: What do you think about a C# 6 like nameof() expression for
Am neither for nor against the proposal. Do not entertain "like"s or
"dislike"s in any field of endeavor. Am certainly not in a position to
prohibit anything relevant JavaScript. Do what thou wilt shall be the whole
of the Law.
Have yet to view a case where code will be "broken" by ```nameof``` not
being a JavaScript feature. "robustness", as already mentioned, is a
subjective adjective that is not capable of being objectively evaluated as
to code itself. That description is based on preference or choice.
In lieu of the proposal being specificed, use the posted code example of
```Object.keys()``` that "works".
```
function func1({userName = void 0} = {}) {
console.assert(userName !== undefined, [{userName}, 'property needs to be
defined'])
}
```
provides a direct indication that the property value is required to be
defined. Note that the example code posted thus far does not first check if
```options``` is passed at all, for which ```nameof``` will not provide any
asssitance.
Usually try to meet requirement by means already available in FOSS
browsers. Have no interest in TypeScript or using an IDE.
FWIW, have no objection to the proposal.
On Fri, Jun 14, 2019 at 7:53 PM Stas Berkov wrote:
> guest271314, what is you point against `nameof` feature?
>
> If you don't like it - don't use it. Why prohibit this feature for
> those who find it beneficial?
>
> I see `nameof` beneficial in following cases
>
> Case 1. Function guard.
> ```
> function func1(options) {
> ...
>if (options.userName == undefined) {
>throw new ParamNullError(nameof options.userName); //
> `ParamNullError` is a custom error, derived from `Error`, composes
> error message like "Parameter cannot be null: userName".
> // `Object.keys({options.userName})[0]` will not work here
>}
> }
> ```
>
> Case 2. Accessing property extended info
> Those ES functions that accept field name as string.
> e.g.
> ```
> const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
> ```
> vs
> ```
> const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
> object1.property1);
> // `Object.keys({options1.property1})[0]` will not work here
> ```
> 2nd variant (proposed) has more chances not to be broken during
> refactoring (robustness).
>
> It would make devs who use IDE more productive and make their life
> easier. Why not give them such possiblity and make them happy?
>
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Re: Re: What do you think about a C# 6 like nameof() expression for
guest271314, what is you point against `nameof` feature?
If you don't like it - don't use it. Why prohibit this feature for
those who find it beneficial?
I see `nameof` beneficial in following cases
Case 1. Function guard.
```
function func1(options) {
...
if (options.userName == undefined) {
throw new ParamNullError(nameof options.userName); //
`ParamNullError` is a custom error, derived from `Error`, composes
error message like "Parameter cannot be null: userName".
// `Object.keys({options.userName})[0]` will not work here
}
}
```
Case 2. Accessing property extended info
Those ES functions that accept field name as string.
e.g.
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
```
vs
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
object1.property1);
// `Object.keys({options1.property1})[0]` will not work here
```
2nd variant (proposed) has more chances not to be broken during
refactoring (robustness).
It would make devs who use IDE more productive and make their life
easier. Why not give them such possiblity and make them happy?
___
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Re: Re: What do you think about a C# 6 like nameof() expression for
> A module namespace isn’t an instance of Module, it’s a module namespace spec object. If it has a name member, that is because the module you imported has an exported binding called name. But what kind of thing it is isn’t what matters. If ```Object.getOwnPropertyDescriptors(ns)``` is used within
RE: Re: What do you think about a C# 6 like nameof() expression for
Since `nameof` does not actually evaluate anything, the following would be
legal:
```
const x = nameof y; // "y"
const y = 1;
```
However, the shorthand property name workaround is not legal due to TDZ:
```
const x = Object.keys({y})[0]; // error due to TDZ
const y = 1;
```
With the shortand property name workaround you also run into the added runtime
overhead of:
* Constructing an object (`{y}`)
* Looking up a property (`Object.keys`)
* Calling a function (`Object.keys`)
* Allocating an array
* Indexing into the array
Whereas `nameof` has *no* runtime overhead, because it would be handled during
static semantics.
From: es-discuss On Behalf Of guest271314
Sent: Friday, June 14, 2019 11:17 AM
To: Stas Berkov
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
Terms such as "more robust", "Less fragile." , "Less mess." are subjective.
"Fragile" how? What is meant by "mess"?
If the proposal is that ```nameof``` is briefer than using shorthand property
names or computed property names to get an identifier as a string, then
```nameof``` would be less code.
> You can rename field/property without fear you break something (using IDE
> refactoring tools).
The use case appears to be within the context of an IDE?
For users that roll their own code by hand at a text editor and do not use an
IDE for composing code (or relying on an IDE for logging errors), am not able
to discern how ```nameof``` is different than using
```Object.getOwnPropertyDescriptors(other).name.value``` or
```Object.keys({userName})[0]```. The actual code will need to be tested in
different browsers anyway before deployment to get the actual results.
If a user has decided they _have_ to use some form of a dynamic "IDE" to
compose code and log errors - while they are writing the code, they can open
DevTools at Chromium or Chrome then select ```Sources``` => ```Snippets``` =>
```New snippet```, where
```
const n = 123;
const n = 456;
```
will highlight the line where the error occurs - during writing the code - the
as a red circle with a transparent "x" in the middle
```Uncaught SyntaxError: Identifier 'n' has already been declared
To run the code press ```ctrl+enter```.
On Fri, Jun 14, 2019 at 5:48 PM Stas Berkov
mailto:stas.ber...@gmail.com>> wrote:
Less fragile. Less mess. You can rename field/property without fear you break
something (using IDE refactoring tools).
With high probablity you will break something when you refactor and have fields
hardcoded as strings.
Someone can object that you can rename strings as well.
Issue here that you can ocassionally change non-related strings that should not
be changed even they match or have matching substring.
On Fri, Jun 14, 2019 at 9:38 PM guest271314
mailto:guest271...@gmail.com>> wrote:
Is Case 1 equivalent to a briefer version of
```
if (userName == undefined) {
throw new Error(`Argument cannot be null:
${Object.keys({userName})[0]}`);
}
```
?
If not, how is ```nameof``` different?
What is the difference between the use of
```message.hasOwnProperty(property)``` and ```nameof msg.expiration_utc_time```?
> You get more robust code.
How is "robust" objectively determined?
On Fri, Jun 14, 2019 at 5:21 PM Stas Berkov
mailto:stas.ber...@gmail.com>> wrote:
ES can befit from `nameof` feature the same way as TS. There is no TS specific
in it.
It was ask to introduce in TS as a workaround since TS is considered as
extention of ES.
Case 1. Function guard.
```
function func1(param1, param2, param3, userName, param4, param5) {
if (userName == undefined) {
throw new ArgumentNullError(nameof userName); // `ArgumentNullError` is
a custom error, derived from `Error`, composes error message like "Argument
cannot be null: userName".
}
}
```
Case 2. Access extended information an object property.
Assume a function
```
function protoPropertyIsSet(message, property) {
return message != null && message.hasOwnProperty(property);
}
```
Then in code you use it as `if (protoPropertyIsSet(msg, "expiration_utc_time"))
{... }`.
Having `nameof` would allow you to do that `if (protoPropertyIsSet(msg, nameof
msg.expiration_utc_time)) {... }`.
You get more robust code.
On Fri, Jun 14, 2019 at 5:46 PM Augusto Moura
mailto:augusto.borg...@gmail.com>> wrote:
Can you list the benefits of having this operators? Maybe with example use cases
If I understand it correctly, the operator fits better in compiled
(and typed) languages, most of the use cases don't apply to dynamic
Javascript
The only legit use case I can think of is helping refactor tools to
rename properties (but even mismatch errors between strings and
properties names can be caught in compile time using modern
Typescript)
Em sex, 14 de jun de 2
RE: Re: What do you think about a C# 6 like nameof() expression for
A module namespace isn’t an instance of `Module`, it’s a module namespace spec
object. If it has a `name` member, that is because the module you imported has
an exported binding called `name`. But what kind of thing it is isn’t what
matters.
`nameof` just returns a string representation of the static symbolic name of
its operand. `nameof` would be used at runtime (i.e. during code execution),
but provides the ability for advanced editors to include it in a “rename”
refactoring.
The operand merely needs to be an identifier that exists within the current
lexical scope. `nameof` would not observe TDZ and would not evaluate any
expression. The ECMAScript static semantics would merely: 1) check that the
identifier provided to `nameof` is the name of something in the current lexical
scope, and 2) replace the expression with a string literal representing the
name.
If `nameof foo.bar` were allowed `nameof` would not actually evaluate
`foo.bar`, but merely result in `”bar”`. `nameof` does not evaluate anything,
it is merely a syntactic transformation by the runtime that becomes a string.
Ron
From: guest271314
Sent: Friday, June 14, 2019 10:07 AM
To: Ron Buckton
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
Not following the module example. Would not ```ns``` be an instance of
```Module``` where ```* as ns``` is used?
For the ```class``` example would ```nameof``` be equivalent to
```Object.getOwnPropertyDescriptors(other).name.value```?
It's not that a language like TypeScript would need this, but rather that users
of an editor like VS Code or WebStorm that have a JavaScript language service
would benefit from it.
Is the primary use case a non-simple text editor; e.g., _not_ gedit (GUI) or
pico or nano (CLI), where the user is depending on the program
for diagnostics (logging and errors)
within a text editor _before_ actually running the code in a given environment
- not to log errors during code execution?
On Fri, Jun 14, 2019 at 4:29 PM Ron Buckton
mailto:ron.buck...@microsoft.com>> wrote:
The 'nameof' operator provides the string name of a static symbol (in
compiler/linker terms, not an ECMAScript 'Symbol'). This is often useful for
diagnostics (logging and errors), and gives developers a way to reduce
repetition. It is also extremely helpful in editors that support symbolic
"rename" refactoring.
While ES functions have a 'name' property, one of the main use cases is to get
a string representation of the name of a thing that isn't itself reified as an
object, such as a variable, parameter, or module namespace:
```
import * as ns from "foo";
nameof ns; // "ns"
let fn = function g() {};
fn.name<https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Ffn.name=02%7C01%7CRon.Buckton%40microsoft.com%7C104ffaa78f6847e3a31708d6f0eab6e3%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636961288212685352=sBP1RXbppYfrzbSFUaC%2F80IBZk1tUDqdxeVmbuTveSE%3D=0>;
// "g"
nameof fn; // "fn"
```
Here is an example of two common use cases:
```
class C {
compare(other) {
if (!(other instanceof C)) {
throw new TypeError(`Invalid argument: ${nameof other} `);
}
set prop(value) {
this._prop = value;
this.emit("propertychanged", nameof prop);
}
}
```
It's not that a language like TypeScript would need this, but rather that users
of an editor like VS Code or WebStorm that have a JavaScript language service
would benefit from it.
Ron
From: es-discuss
mailto:es-discuss-boun...@mozilla.org>> on
behalf of guest271314 mailto:guest271...@gmail.com>>
Sent: Friday, June 14, 2019 9:05:55 AM
To: Stas Berkov
Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org>
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
Have not tried TypeScript. What are the use cases for JavaScript where
TypeScript is not used? Does ```nameof()``` check if an object has a specific
property name defined (```"MutationObserver" in window```;
```window.MutationObserver```; ```"document" in globalThis```)?
On Fri, Jun 14, 2019 at 1:05 PM Stas Berkov
mailto:stas.ber...@gmail.com>> wrote:
Can we revisit this issue?
In C# there is `nameof`, in Swift you can do the same by calling
```
let keyPath = \Person.mother.firstName
NSPredicate(format: "%K == %@", keyPath, "Andrew")
```
Let's introduce `nameof` in ES, please.
Devs from TypeScript don't want to introduce this feature in TypeScript unless
it is available in ES ( https://github.com/microsoft/TypeScript/issues/1579 )
This feature is eagarly being asked by TypeScript community.
I understand there are couple issues related to `nameof` feature in ES. They
are: minification and what to do if user already has `nameof` function.
Minification.
1. If your code to be minimized be prepared that
Re: Re: What do you think about a C# 6 like nameof() expression for
Terms such as "more robust", "Less fragile." , "Less mess." are subjective.
"Fragile" how? What is meant by "mess"?
If the proposal is that ```nameof``` is briefer than using shorthand
property names or computed property names to get an identifier as a string,
then ```nameof``` would be less code.
> You can rename field/property without fear you break something (using IDE
refactoring tools).
The use case appears to be within the context of an IDE?
For users that roll their own code by hand at a text editor and do not use
an IDE for composing code (or relying on an IDE for logging errors), am not
able to discern how ```nameof``` is different than using
```Object.getOwnPropertyDescriptors(other).name.value``` or
```Object.keys({userName})[0]```. The actual code will need to be tested in
different browsers anyway before deployment to get the actual results.
If a user has decided they _have_ to use some form of a dynamic "IDE" to
compose code and log errors - while they are writing the code, they can
open DevTools at Chromium or Chrome then select ```Sources``` =>
```Snippets``` => ```New snippet```, where
```
const n = 123;
const n = 456;
```
will highlight the line where the error occurs - during writing the code -
the as a red circle with a transparent "x" in the middle
```Uncaught SyntaxError: Identifier 'n' has already been declared
To run the code press ```ctrl+enter```.
On Fri, Jun 14, 2019 at 5:48 PM Stas Berkov wrote:
> Less fragile. Less mess. You can rename field/property without fear you
> break something (using IDE refactoring tools).
> With high probablity you will break something when you refactor and have
> fields hardcoded as strings.
> Someone can object that you can rename strings as well.
> Issue here that you can ocassionally change non-related strings that
> should not be changed even they match or have matching substring.
>
> On Fri, Jun 14, 2019 at 9:38 PM guest271314 wrote:
>
>> Is Case 1 equivalent to a briefer version of
>>
>> ```
>>if (userName == undefined) {
>>throw new Error(`Argument cannot be null:
>> ${Object.keys({userName})[0]}`);
>>}
>> ```
>>
>> ?
>>
>> If not, how is ```nameof``` different?
>>
>> What is the difference between the use of
>> ```message.hasOwnProperty(property)```
>> and ```nameof msg.expiration_utc_time```?
>>
>> > You get more robust code.
>>
>> How is "robust" objectively determined?
>>
>>
>>
>>
>> On Fri, Jun 14, 2019 at 5:21 PM Stas Berkov
>> wrote:
>>
>>> ES can befit from `nameof` feature the same way as TS. There is no TS
>>> specific in it.
>>> It was ask to introduce in TS as a workaround since TS is considered as
>>> extention of ES.
>>>
>>> Case 1. Function guard.
>>> ```
>>> function func1(param1, param2, param3, userName, param4, param5) {
>>>if (userName == undefined) {
>>>throw new ArgumentNullError(nameof userName); //
>>> `ArgumentNullError` is a custom error, derived from `Error`, composes error
>>> message like "Argument cannot be null: userName".
>>>}
>>> }
>>> ```
>>>
>>> Case 2. Access extended information an object property.
>>> Assume a function
>>> ```
>>> function protoPropertyIsSet(message, property) {
>>> return message != null && message.hasOwnProperty(property);
>>> }
>>> ```
>>> Then in code you use it as `if (protoPropertyIsSet(msg,
>>> "expiration_utc_time")) {... }`.
>>> Having `nameof` would allow you to do that `if (protoPropertyIsSet(msg,
>>> nameof msg.expiration_utc_time)) {... }`.
>>> You get more robust code.
>>>
>>> On Fri, Jun 14, 2019 at 5:46 PM Augusto Moura
>>> wrote:
>>>
Can you list the benefits of having this operators? Maybe with example
use cases
If I understand it correctly, the operator fits better in compiled
(and typed) languages, most of the use cases don't apply to dynamic
Javascript
The only legit use case I can think of is helping refactor tools to
rename properties (but even mismatch errors between strings and
properties names can be caught in compile time using modern
Typescript)
Em sex, 14 de jun de 2019 às 10:05, Stas Berkov
escreveu:
>
> Can we revisit this issue?
>
>
> In C# there is `nameof`, in Swift you can do the same by calling
>
> ```
>
> let keyPath = \Person.mother.firstName
>
> NSPredicate(format: "%K == %@", keyPath, "Andrew")
>
> ```
>
> Let's introduce `nameof` in ES, please.
>
>
> Devs from TypeScript don't want to introduce this feature in
TypeScript unless it is available in ES (
https://github.com/microsoft/TypeScript/issues/1579 )
>
> This feature is eagarly being asked by TypeScript community.
>
>
> I understand there are couple issues related to `nameof` feature in
ES. They are: minification and what to do if user already has `nameof`
function.
>
>
> Minification.
>
> 1. If your code to be
Re: Re: What do you think about a C# 6 like nameof() expression for
> Is Case 1 equivalent to a briefer version of
> ```
if (userName == undefined) {
throw new Error(`Argument cannot be null:
${Object.keys({userName})[0]}`);
}
```
Less readable but in this simple case might work.
What if we do the following:
Case 1. Function guard.
```
function func1(options) {
...
if (options.userName == undefined) {
throw new ParamNullError(nameof options.userName); //
`ParamNullError` is a custom error, derived from `Error`, composes error
message like "Argument cannot be null: userName".
}
}
```
Case 2. Accessing property extended info
e.g.
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, 'property1');
```
vs
```
const descriptor1 = Object.getOwnPropertyDescriptor(object1, nameof
object1.property1);
```
2nd variant (proposed) has more chances not to be broken during refactoring
(robustness).
On Fri, Jun 14, 2019 at 9:48 PM Stas Berkov wrote:
> Less fragile. Less mess. You can rename field/property without fear you
> break something (using IDE refactoring tools).
> With high probablity you will break something when you refactor and have
> fields hardcoded as strings.
> Someone can object that you can rename strings as well.
> Issue here that you can ocassionally change non-related strings that
> should not be changed even they match or have matching substring.
>
> On Fri, Jun 14, 2019 at 9:38 PM guest271314 wrote:
>
>> Is Case 1 equivalent to a briefer version of
>>
>> ```
>>if (userName == undefined) {
>>throw new Error(`Argument cannot be null:
>> ${Object.keys({userName})[0]}`);
>>}
>> ```
>>
>> ?
>>
>> If not, how is ```nameof``` different?
>>
>> What is the difference between the use of
>> ```message.hasOwnProperty(property)```
>> and ```nameof msg.expiration_utc_time```?
>>
>> > You get more robust code.
>>
>> How is "robust" objectively determined?
>>
>>
>>
>>
>> On Fri, Jun 14, 2019 at 5:21 PM Stas Berkov
>> wrote:
>>
>>> ES can befit from `nameof` feature the same way as TS. There is no TS
>>> specific in it.
>>> It was ask to introduce in TS as a workaround since TS is considered as
>>> extention of ES.
>>>
>>> Case 1. Function guard.
>>> ```
>>> function func1(param1, param2, param3, userName, param4, param5) {
>>>if (userName == undefined) {
>>>throw new ArgumentNullError(nameof userName); //
>>> `ArgumentNullError` is a custom error, derived from `Error`, composes error
>>> message like "Argument cannot be null: userName".
>>>}
>>> }
>>> ```
>>>
>>> Case 2. Access extended information an object property.
>>> Assume a function
>>> ```
>>> function protoPropertyIsSet(message, property) {
>>> return message != null && message.hasOwnProperty(property);
>>> }
>>> ```
>>> Then in code you use it as `if (protoPropertyIsSet(msg,
>>> "expiration_utc_time")) {... }`.
>>> Having `nameof` would allow you to do that `if (protoPropertyIsSet(msg,
>>> nameof msg.expiration_utc_time)) {... }`.
>>> You get more robust code.
>>>
>>> On Fri, Jun 14, 2019 at 5:46 PM Augusto Moura
>>> wrote:
>>>
Can you list the benefits of having this operators? Maybe with example
use cases
If I understand it correctly, the operator fits better in compiled
(and typed) languages, most of the use cases don't apply to dynamic
Javascript
The only legit use case I can think of is helping refactor tools to
rename properties (but even mismatch errors between strings and
properties names can be caught in compile time using modern
Typescript)
Em sex, 14 de jun de 2019 às 10:05, Stas Berkov
escreveu:
>
> Can we revisit this issue?
>
>
> In C# there is `nameof`, in Swift you can do the same by calling
>
> ```
>
> let keyPath = \Person.mother.firstName
>
> NSPredicate(format: "%K == %@", keyPath, "Andrew")
>
> ```
>
> Let's introduce `nameof` in ES, please.
>
>
> Devs from TypeScript don't want to introduce this feature in
TypeScript unless it is available in ES (
https://github.com/microsoft/TypeScript/issues/1579 )
>
> This feature is eagarly being asked by TypeScript community.
>
>
> I understand there are couple issues related to `nameof` feature in
ES. They are: minification and what to do if user already has `nameof`
function.
>
>
> Minification.
>
> 1. If your code to be minimized be prepared that variable names will
also change.
>
> 2. (just a possibility) Minimizer can have option to replace
`nameof(someVar)` with result of `nameof` function.
>
>
>
> What if user already has `nameof` function.
>
> 1. To maintain status quo we can user `nameof` function having
priority over newly introduced language feature.
>
> 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (//
returns "userName" string)
>
>
Re: Re: What do you think about a C# 6 like nameof() expression for
Less fragile. Less mess. You can rename field/property without fear you
break something (using IDE refactoring tools).
With high probablity you will break something when you refactor and have
fields hardcoded as strings.
Someone can object that you can rename strings as well.
Issue here that you can ocassionally change non-related strings that should
not be changed even they match or have matching substring.
On Fri, Jun 14, 2019 at 9:38 PM guest271314 wrote:
> Is Case 1 equivalent to a briefer version of
>
> ```
>if (userName == undefined) {
>throw new Error(`Argument cannot be null:
> ${Object.keys({userName})[0]}`);
>}
> ```
>
> ?
>
> If not, how is ```nameof``` different?
>
> What is the difference between the use of
> ```message.hasOwnProperty(property)```
> and ```nameof msg.expiration_utc_time```?
>
> > You get more robust code.
>
> How is "robust" objectively determined?
>
>
>
>
> On Fri, Jun 14, 2019 at 5:21 PM Stas Berkov wrote:
>
>> ES can befit from `nameof` feature the same way as TS. There is no TS
>> specific in it.
>> It was ask to introduce in TS as a workaround since TS is considered as
>> extention of ES.
>>
>> Case 1. Function guard.
>> ```
>> function func1(param1, param2, param3, userName, param4, param5) {
>>if (userName == undefined) {
>>throw new ArgumentNullError(nameof userName); //
>> `ArgumentNullError` is a custom error, derived from `Error`, composes error
>> message like "Argument cannot be null: userName".
>>}
>> }
>> ```
>>
>> Case 2. Access extended information an object property.
>> Assume a function
>> ```
>> function protoPropertyIsSet(message, property) {
>> return message != null && message.hasOwnProperty(property);
>> }
>> ```
>> Then in code you use it as `if (protoPropertyIsSet(msg,
>> "expiration_utc_time")) {... }`.
>> Having `nameof` would allow you to do that `if (protoPropertyIsSet(msg,
>> nameof msg.expiration_utc_time)) {... }`.
>> You get more robust code.
>>
>> On Fri, Jun 14, 2019 at 5:46 PM Augusto Moura
>> wrote:
>>
>>> Can you list the benefits of having this operators? Maybe with example
>>> use cases
>>>
>>> If I understand it correctly, the operator fits better in compiled
>>> (and typed) languages, most of the use cases don't apply to dynamic
>>> Javascript
>>> The only legit use case I can think of is helping refactor tools to
>>> rename properties (but even mismatch errors between strings and
>>> properties names can be caught in compile time using modern
>>> Typescript)
>>>
>>> Em sex, 14 de jun de 2019 às 10:05, Stas Berkov
>>> escreveu:
>>> >
>>> > Can we revisit this issue?
>>> >
>>> >
>>> > In C# there is `nameof`, in Swift you can do the same by calling
>>> >
>>> > ```
>>> >
>>> > let keyPath = \Person.mother.firstName
>>> >
>>> > NSPredicate(format: "%K == %@", keyPath, "Andrew")
>>> >
>>> > ```
>>> >
>>> > Let's introduce `nameof` in ES, please.
>>> >
>>> >
>>> > Devs from TypeScript don't want to introduce this feature in
>>> TypeScript unless it is available in ES (
>>> https://github.com/microsoft/TypeScript/issues/1579 )
>>> >
>>> > This feature is eagarly being asked by TypeScript community.
>>> >
>>> >
>>> > I understand there are couple issues related to `nameof` feature in
>>> ES. They are: minification and what to do if user already has `nameof`
>>> function.
>>> >
>>> >
>>> > Minification.
>>> >
>>> > 1. If your code to be minimized be prepared that variable names will
>>> also change.
>>> >
>>> > 2. (just a possibility) Minimizer can have option to replace
>>> `nameof(someVar)` with result of `nameof` function.
>>> >
>>> >
>>> >
>>> > What if user already has `nameof` function.
>>> >
>>> > 1. To maintain status quo we can user `nameof` function having
>>> priority over newly introduced language feature.
>>> >
>>> > 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (//
>>> returns "userName" string)
>>> >
>>> > ___
>>> > es-discuss mailing list
>>> > es-discuss@mozilla.org
>>> > https://mail.mozilla.org/listinfo/es-discuss
>>>
>>>
>>>
>>> --
>>> Atenciosamente,
>>>
>>> Augusto Borges de Moura
>>>
>> ___
>> es-discuss mailing list
>> es-discuss@mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>>
>
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
Is Case 1 equivalent to a briefer version of
```
if (userName == undefined) {
throw new Error(`Argument cannot be null:
${Object.keys({userName})[0]}`);
}
```
?
If not, how is ```nameof``` different?
What is the difference between the use of
```message.hasOwnProperty(property)```
and ```nameof msg.expiration_utc_time```?
> You get more robust code.
How is "robust" objectively determined?
On Fri, Jun 14, 2019 at 5:21 PM Stas Berkov wrote:
> ES can befit from `nameof` feature the same way as TS. There is no TS
> specific in it.
> It was ask to introduce in TS as a workaround since TS is considered as
> extention of ES.
>
> Case 1. Function guard.
> ```
> function func1(param1, param2, param3, userName, param4, param5) {
>if (userName == undefined) {
>throw new ArgumentNullError(nameof userName); //
> `ArgumentNullError` is a custom error, derived from `Error`, composes error
> message like "Argument cannot be null: userName".
>}
> }
> ```
>
> Case 2. Access extended information an object property.
> Assume a function
> ```
> function protoPropertyIsSet(message, property) {
> return message != null && message.hasOwnProperty(property);
> }
> ```
> Then in code you use it as `if (protoPropertyIsSet(msg,
> "expiration_utc_time")) {... }`.
> Having `nameof` would allow you to do that `if (protoPropertyIsSet(msg,
> nameof msg.expiration_utc_time)) {... }`.
> You get more robust code.
>
> On Fri, Jun 14, 2019 at 5:46 PM Augusto Moura
> wrote:
>
>> Can you list the benefits of having this operators? Maybe with example
>> use cases
>>
>> If I understand it correctly, the operator fits better in compiled
>> (and typed) languages, most of the use cases don't apply to dynamic
>> Javascript
>> The only legit use case I can think of is helping refactor tools to
>> rename properties (but even mismatch errors between strings and
>> properties names can be caught in compile time using modern
>> Typescript)
>>
>> Em sex, 14 de jun de 2019 às 10:05, Stas Berkov
>> escreveu:
>> >
>> > Can we revisit this issue?
>> >
>> >
>> > In C# there is `nameof`, in Swift you can do the same by calling
>> >
>> > ```
>> >
>> > let keyPath = \Person.mother.firstName
>> >
>> > NSPredicate(format: "%K == %@", keyPath, "Andrew")
>> >
>> > ```
>> >
>> > Let's introduce `nameof` in ES, please.
>> >
>> >
>> > Devs from TypeScript don't want to introduce this feature in TypeScript
>> unless it is available in ES (
>> https://github.com/microsoft/TypeScript/issues/1579 )
>> >
>> > This feature is eagarly being asked by TypeScript community.
>> >
>> >
>> > I understand there are couple issues related to `nameof` feature in ES.
>> They are: minification and what to do if user already has `nameof` function.
>> >
>> >
>> > Minification.
>> >
>> > 1. If your code to be minimized be prepared that variable names will
>> also change.
>> >
>> > 2. (just a possibility) Minimizer can have option to replace
>> `nameof(someVar)` with result of `nameof` function.
>> >
>> >
>> >
>> > What if user already has `nameof` function.
>> >
>> > 1. To maintain status quo we can user `nameof` function having priority
>> over newly introduced language feature.
>> >
>> > 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (//
>> returns "userName" string)
>> >
>> > ___
>> > es-discuss mailing list
>> > es-discuss@mozilla.org
>> > https://mail.mozilla.org/listinfo/es-discuss
>>
>>
>>
>> --
>> Atenciosamente,
>>
>> Augusto Borges de Moura
>>
> ___
> es-discuss mailing list
> es-discuss@mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
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Re: Re: What do you think about a C# 6 like nameof() expression for
ES can befit from `nameof` feature the same way as TS. There is no TS
specific in it.
It was ask to introduce in TS as a workaround since TS is considered as
extention of ES.
Case 1. Function guard.
```
function func1(param1, param2, param3, userName, param4, param5) {
if (userName == undefined) {
throw new ArgumentNullError(nameof userName); // `ArgumentNullError`
is a custom error, derived from `Error`, composes error message like
"Argument cannot be null: userName".
}
}
```
Case 2. Access extended information an object property.
Assume a function
```
function protoPropertyIsSet(message, property) {
return message != null && message.hasOwnProperty(property);
}
```
Then in code you use it as `if (protoPropertyIsSet(msg,
"expiration_utc_time")) {... }`.
Having `nameof` would allow you to do that `if (protoPropertyIsSet(msg,
nameof msg.expiration_utc_time)) {... }`.
You get more robust code.
On Fri, Jun 14, 2019 at 5:46 PM Augusto Moura
wrote:
> Can you list the benefits of having this operators? Maybe with example use
> cases
>
> If I understand it correctly, the operator fits better in compiled
> (and typed) languages, most of the use cases don't apply to dynamic
> Javascript
> The only legit use case I can think of is helping refactor tools to
> rename properties (but even mismatch errors between strings and
> properties names can be caught in compile time using modern
> Typescript)
>
> Em sex, 14 de jun de 2019 às 10:05, Stas Berkov
> escreveu:
> >
> > Can we revisit this issue?
> >
> >
> > In C# there is `nameof`, in Swift you can do the same by calling
> >
> > ```
> >
> > let keyPath = \Person.mother.firstName
> >
> > NSPredicate(format: "%K == %@", keyPath, "Andrew")
> >
> > ```
> >
> > Let's introduce `nameof` in ES, please.
> >
> >
> > Devs from TypeScript don't want to introduce this feature in TypeScript
> unless it is available in ES (
> https://github.com/microsoft/TypeScript/issues/1579 )
> >
> > This feature is eagarly being asked by TypeScript community.
> >
> >
> > I understand there are couple issues related to `nameof` feature in ES.
> They are: minification and what to do if user already has `nameof` function.
> >
> >
> > Minification.
> >
> > 1. If your code to be minimized be prepared that variable names will
> also change.
> >
> > 2. (just a possibility) Minimizer can have option to replace
> `nameof(someVar)` with result of `nameof` function.
> >
> >
> >
> > What if user already has `nameof` function.
> >
> > 1. To maintain status quo we can user `nameof` function having priority
> over newly introduced language feature.
> >
> > 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns
> "userName" string)
> >
> > ___
> > es-discuss mailing list
> > es-discuss@mozilla.org
> > https://mail.mozilla.org/listinfo/es-discuss
>
>
>
> --
> Atenciosamente,
>
> Augusto Borges de Moura
>
___
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Re: Re: What do you think about a C# 6 like nameof() expression for
Not following the module example. Would not ```ns``` be an instance of
```Module``` where ```* as ns``` is used?
For the ```class``` example would ```nameof``` be equivalent to
```Object.getOwnPropertyDescriptors(other).name.value```?
It's not that a language like TypeScript would need this, but rather that
> users of an editor like VS Code or WebStorm that have a JavaScript language
> service would benefit from it.
Is the primary use case a non-simple text editor; e.g., _not_ gedit (GUI)
or pico or nano (CLI), where the user is depending on the program
for diagnostics (logging and errors)
within a text editor _before_ actually running the code in a given
environment - not to log errors during code execution?
On Fri, Jun 14, 2019 at 4:29 PM Ron Buckton
wrote:
> The 'nameof' operator provides the string name of a static symbol (in
> compiler/linker terms, not an ECMAScript 'Symbol'). This is often useful
> for diagnostics (logging and errors), and gives developers a way to reduce
> repetition. It is also extremely helpful in editors that support symbolic
> "rename" refactoring.
>
> While ES functions have a 'name' property, one of the main use cases is to
> get a string representation of the name of a thing that isn't itself
> reified as an object, such as a variable, parameter, or module namespace:
>
> ```
> import * as ns from "foo";
>
> nameof ns; // "ns"
>
> let fn = function g() {};
> fn.name; // "g"
> nameof fn; // "fn"
> ```
>
> Here is an example of two common use cases:
>
> ```
> class C {
> compare(other) {
> if (!(other instanceof C)) {
> throw new TypeError(`Invalid argument: ${nameof other} `);
> }
>
> set prop(value) {
> this._prop = value;
> this.emit("propertychanged", nameof prop);
> }
> }
> ```
>
> It's not that a language like TypeScript would need this, but rather that
> users of an editor like VS Code or WebStorm that have a JavaScript language
> service would benefit from it.
>
> Ron
> ------------------
> *From:* es-discuss on behalf of
> guest271314
> *Sent:* Friday, June 14, 2019 9:05:55 AM
> *To:* Stas Berkov
> *Cc:* es-discuss@mozilla.org
> *Subject:* Re: Re: What do you think about a C# 6 like nameof()
> expression for
>
> Have not tried TypeScript. What are the use cases for JavaScript where
> TypeScript is not used? Does ```nameof()``` check if an object has a
> specific property name defined (```"MutationObserver" in window```;
> ```window.MutationObserver```; ```"document" in globalThis```)?
>
> On Fri, Jun 14, 2019 at 1:05 PM Stas Berkov wrote:
>
>> Can we revisit this issue?
>>
>>
>> In C# there is `nameof`, in Swift you can do the same by calling
>>
>> ```
>>
>> let keyPath = \Person.mother.firstName
>>
>> NSPredicate(format: "%K == %@", keyPath, "Andrew")
>>
>> ```
>>
>> Let's introduce `nameof` in ES, please.
>>
>>
>> Devs from TypeScript don't want to introduce this feature in TypeScript
>> unless it is available in ES (
>> https://github.com/microsoft/TypeScript/issues/1579
>> <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fmicrosoft%2FTypeScript%2Fissues%2F1579=02%7C01%7Cron.buckton%40microsoft.com%7Ceab205c181fc4322b92208d6f0e23843%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636961251760815455=qeHDrSKENDcCczwAJFoOqAro5lo9NcXzBJA5eCXx9rA%3D=0>
>> )
>>
>> This feature is eagarly being asked by TypeScript community.
>>
>>
>> I understand there are couple issues related to `nameof` feature in ES.
>> They are: minification and what to do if user already has `nameof` function.
>>
>>
>> Minification.
>>
>> 1. If your code to be minimized be prepared that variable names will also
>> change.
>>
>> 2. (just a possibility) Minimizer can have option to replace
>> `nameof(someVar)` with result of `nameof` function.
>>
>>
>>
>> What if user already has `nameof` function.
>>
>> 1. To maintain status quo we can user `nameof` function having priority
>> over newly introduced language feature.
>>
>> 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns
>> "userName" string)
>> ___
>> es-discuss mailing list
>> es-discuss@mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>> <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.mozilla.org%2Flistinfo%2Fes-discuss=02%7C01%7Cron.buckton%40microsoft.com%7Ceab205c181fc4322b92208d6f0e23843%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636961251760815455=tJnR7LnmHuPm4dJOocLRVKUnaWxZvP5uAhywV2M25lM%3D=0>
>>
>
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Re: Re: What do you think about a C# 6 like nameof() expression for
The 'nameof' operator provides the string name of a static symbol (in
compiler/linker terms, not an ECMAScript 'Symbol'). This is often useful for
diagnostics (logging and errors), and gives developers a way to reduce
repetition. It is also extremely helpful in editors that support symbolic
"rename" refactoring.
While ES functions have a 'name' property, one of the main use cases is to get
a string representation of the name of a thing that isn't itself reified as an
object, such as a variable, parameter, or module namespace:
```
import * as ns from "foo";
nameof ns; // "ns"
let fn = function g() {};
fn.name; // "g"
nameof fn; // "fn"
```
Here is an example of two common use cases:
```
class C {
compare(other) {
if (!(other instanceof C)) {
throw new TypeError(`Invalid argument: ${nameof other} `);
}
set prop(value) {
this._prop = value;
this.emit("propertychanged", nameof prop);
}
}
```
It's not that a language like TypeScript would need this, but rather that users
of an editor like VS Code or WebStorm that have a JavaScript language service
would benefit from it.
Ron
From: es-discuss on behalf of guest271314
Sent: Friday, June 14, 2019 9:05:55 AM
To: Stas Berkov
Cc: es-discuss@mozilla.org
Subject: Re: Re: What do you think about a C# 6 like nameof() expression for
Have not tried TypeScript. What are the use cases for JavaScript where
TypeScript is not used? Does ```nameof()``` check if an object has a specific
property name defined (```"MutationObserver" in window```;
```window.MutationObserver```; ```"document" in globalThis```)?
On Fri, Jun 14, 2019 at 1:05 PM Stas Berkov
mailto:stas.ber...@gmail.com>> wrote:
Can we revisit this issue?
In C# there is `nameof`, in Swift you can do the same by calling
```
let keyPath = \Person.mother.firstName
NSPredicate(format: "%K == %@", keyPath, "Andrew")
```
Let's introduce `nameof` in ES, please.
Devs from TypeScript don't want to introduce this feature in TypeScript unless
it is available in ES (
https://github.com/microsoft/TypeScript/issues/1579<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fmicrosoft%2FTypeScript%2Fissues%2F1579=02%7C01%7Cron.buckton%40microsoft.com%7Ceab205c181fc4322b92208d6f0e23843%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636961251760815455=qeHDrSKENDcCczwAJFoOqAro5lo9NcXzBJA5eCXx9rA%3D=0>
)
This feature is eagarly being asked by TypeScript community.
I understand there are couple issues related to `nameof` feature in ES. They
are: minification and what to do if user already has `nameof` function.
Minification.
1. If your code to be minimized be prepared that variable names will also
change.
2. (just a possibility) Minimizer can have option to replace `nameof(someVar)`
with result of `nameof` function.
What if user already has `nameof` function.
1. To maintain status quo we can user `nameof` function having priority over
newly introduced language feature.
2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns
"userName" string)
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Re: Re: What do you think about a C# 6 like nameof() expression for
Have not tried TypeScript. What are the use cases for JavaScript where TypeScript is not used? Does ```nameof()``` check if an object has a specific property name defined (```"MutationObserver" in window```; ```window.MutationObserver```; ```"document" in globalThis```)? On Fri, Jun 14, 2019 at 1:05 PM Stas Berkov wrote: > Can we revisit this issue? > > > In C# there is `nameof`, in Swift you can do the same by calling > > ``` > > let keyPath = \Person.mother.firstName > > NSPredicate(format: "%K == %@", keyPath, "Andrew") > > ``` > > Let's introduce `nameof` in ES, please. > > > Devs from TypeScript don't want to introduce this feature in TypeScript > unless it is available in ES ( > https://github.com/microsoft/TypeScript/issues/1579 ) > > This feature is eagarly being asked by TypeScript community. > > > I understand there are couple issues related to `nameof` feature in ES. > They are: minification and what to do if user already has `nameof` function. > > > Minification. > > 1. If your code to be minimized be prepared that variable names will also > change. > > 2. (just a possibility) Minimizer can have option to replace > `nameof(someVar)` with result of `nameof` function. > > > > What if user already has `nameof` function. > > 1. To maintain status quo we can user `nameof` function having priority > over newly introduced language feature. > > 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns > "userName" string) > ___ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
Can you list the benefits of having this operators? Maybe with example use cases If I understand it correctly, the operator fits better in compiled (and typed) languages, most of the use cases don't apply to dynamic Javascript The only legit use case I can think of is helping refactor tools to rename properties (but even mismatch errors between strings and properties names can be caught in compile time using modern Typescript) Em sex, 14 de jun de 2019 às 10:05, Stas Berkov escreveu: > > Can we revisit this issue? > > > In C# there is `nameof`, in Swift you can do the same by calling > > ``` > > let keyPath = \Person.mother.firstName > > NSPredicate(format: "%K == %@", keyPath, "Andrew") > > ``` > > Let's introduce `nameof` in ES, please. > > > Devs from TypeScript don't want to introduce this feature in TypeScript > unless it is available in ES ( > https://github.com/microsoft/TypeScript/issues/1579 ) > > This feature is eagarly being asked by TypeScript community. > > > I understand there are couple issues related to `nameof` feature in ES. They > are: minification and what to do if user already has `nameof` function. > > > Minification. > > 1. If your code to be minimized be prepared that variable names will also > change. > > 2. (just a possibility) Minimizer can have option to replace > `nameof(someVar)` with result of `nameof` function. > > > > What if user already has `nameof` function. > > 1. To maintain status quo we can user `nameof` function having priority over > newly introduced language feature. > > 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns > "userName" string) > > ___ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss -- Atenciosamente, Augusto Borges de Moura ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: Re: What do you think about a C# 6 like nameof() expression for
Can we revisit this issue? In C# there is `nameof`, in Swift you can do the same by calling ``` let keyPath = \Person.mother.firstName NSPredicate(format: "%K == %@", keyPath, "Andrew") ``` Let's introduce `nameof` in ES, please. Devs from TypeScript don't want to introduce this feature in TypeScript unless it is available in ES ( https://github.com/microsoft/TypeScript/issues/1579 ) This feature is eagarly being asked by TypeScript community. I understand there are couple issues related to `nameof` feature in ES. They are: minification and what to do if user already has `nameof` function. Minification. 1. If your code to be minimized be prepared that variable names will also change. 2. (just a possibility) Minimizer can have option to replace `nameof(someVar)` with result of `nameof` function. What if user already has `nameof` function. 1. To maintain status quo we can user `nameof` function having priority over newly introduced language feature. 2. OR we can use `typeof` syntax, e.g. `nameof msg.userName` (// returns "userName" string) ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
