Re: Re: ES6 iteration over object values
Returning just arrays will be inconsistent with the same name methods that sit on prototypes of Array, Map, etc. Yes, Object.keys(...) poisons the iterators idea, but I think these better to be iterators. Or, if Object.values and Object.entries will start returning simple arrays (which of cours is consistent with Object.keys), then probably the iterator method names are better to rename. (Object.keysIterator(), or something, don't know yet -- verbose, but does what it says) Anyhow, since it's ES7, there's a plenty of time to discuss. Dmitry On Sunday, September 28, 2014, Rick Waldron waldron.r...@gmail.com wrote: On Sun, Sep 28, 2014 at 11:28 AM, Mark Volkmann r.mark.volkm...@gmail.com javascript:_e(%7B%7D,'cvml','r.mark.volkm...@gmail.com'); wrote: What happened to adding the Object.values and Object.entries methods? There was some discussion that led me to believe these would be in ES6. Are they now targeted for ES7? Yes, proposed by me and always for ES7 https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-04/apr-9.md#51-objectentries-objectvalues I will complete the necessary tasks for Stage 1 at next meeting. Rick ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: Re: ES6 iteration over object values
What happened to adding the Object.values and Object.entries methods? There was some discussion that led me to believe these would be in ES6. Are they now targeted for ES7? -- R. Mark Volkmann Object Computing, Inc. ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: Re: ES6 iteration over object values
On Sun, Sep 28, 2014 at 11:28 AM, Mark Volkmann r.mark.volkm...@gmail.com wrote: What happened to adding the Object.values and Object.entries methods? There was some discussion that led me to believe these would be in ES6. Are they now targeted for ES7? Yes, proposed by me and always for ES7 https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-04/apr-9.md#51-objectentries-objectvalues I will complete the necessary tasks for Stage 1 at next meeting. Rick ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
Le 16/03/2014 00:45, Rick Waldron a écrit :
On Sat, Mar 15, 2014 at 7:38 PM, Jason Orendorff
jason.orendo...@gmail.com mailto:jason.orendo...@gmail.com wrote:
On Sat, Mar 15, 2014 at 5:19 PM, David Bruant bruan...@gmail.com
mailto:bruan...@gmail.com wrote:
Even if error prone, I'd be interested to hear about arguments
in the sense
that the risk outweighs the benefits. Iterable-by-default
objects is a nice
battery included feature.
I'm pretty sure es-discuss has been over this, but it doesn't hurt
to restate:
1. This would mean that evolving any object in any API from *not*
having an @@iterator method to providing its own @@iterator method
would be a backward compatibility risk. Existing code might be using
the default @@iterator to enumerate the object's properties.
2. The default Object.prototype.@@iterator would not appear on
Object.create(null), so the one kind of object people would most want
to have this behavior (Objects specifically created for use as
dictionaries) would be the only kind of object that wouldn't have it.
A separate function would be better---you could apply it to anything
with properties.
Either reason alone would be enough, but to me #1 is a killer.
Platform evolution hazards are bad news. You get stuff like
Array.prototype.values being backed out of browsers, and then you get
stuff like @@unscopables.
I'd like to see an Object.entries method, and Object.values for
completeness. Same visibility rules as Object.keys.
for (let [k, v] of Object.entries(myObj)) {
// do something with k and v
}
Very enthusiastically agree---these would be excellent additions that
balance nicely with Dict (null __proto_ b/w keys, values, entries),
along with all of the builts-ins that received keys, values and
entries on their prototypes in ES6.
Alright, convinced too.
Thanks :-)
David
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
Le 15/03/2014 01:32, Brandon Benvie a écrit :
On 3/14/2014 5:16 PM, Mark Volkmann wrote:
Does ES6 add any new ways to iterate over the values in an object?
I've done a lot of searching, but haven't seen anything.
I'm wondering if there is something more elegant than this:
Object.keys(myObj).forEach(function (key) {
let obj = myObj[key];
// do something with obj
});
Not built in, but ES6 does provide a better story for this using
generators and for-of:
```js
// using a generator function
function* entries(obj) {
for (let key of Object.keys(obj)) {
yield [key, obj[key]];
}
}
// an alternative version using a generator expression
function entries(obj) {
return (for (key of Object.keys(obj)) [key, obj[key]]);
}
for (let [key, value] of entries(myObj)) {
// do something with key|value
}
```
Currently, there is no default Object.prototype.@@iterator, so
for-of'ing over an object throws a TypeError which isn't really a useful
default.
No having a default @@iterator also makes that Map({a:1, b:2}) throws
which is unfortunate.
Should what you just wrote be made the default
Object.prototype.@@iterator? It is compatible with the signature the Map
constructor expects too.
David
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
Le 15/03/2014 22:51, C. Scott Ananian a écrit :
It would be nicer to add an Object.entries() method that would return
that iterator.
Object.prototype.entries or Object.entries(obj)?
That would be less error prone than adding a default iterator to every
object.
The world has survived for-in and its weirdo unchangeable
enumerable+proto-climbing rules and that was error prone.
Now we can control enumerability of things that are added to the
prototype and the proposed default-but-still-overridable semantics is to
iterate only over own properties. It's less clear to me that the
proposed semantics is error prone.
The world has also evolved to a point where tooling can be written to
warn about non-overridden @@iterable property for a given class (I
feel like it is something TypeScript could do at least).
Even if error prone, I'd be interested to hear about arguments in the
sense that the risk outweighs the benefits. Iterable-by-default objects
is a nice battery included feature.
David
--scott
On Mar 15, 2014 7:42 AM, David Bruant bruan...@gmail.com
mailto:bruan...@gmail.com wrote:
Le 15/03/2014 01:32, Brandon Benvie a écrit :
On 3/14/2014 5:16 PM, Mark Volkmann wrote:
Does ES6 add any new ways to iterate over the values in an
object?
I've done a lot of searching, but haven't seen anything.
I'm wondering if there is something more elegant than this:
Object.keys(myObj).forEach(function (key) {
let obj = myObj[key];
// do something with obj
});
Not built in, but ES6 does provide a better story for this
using generators and for-of:
```js
// using a generator function
function* entries(obj) {
for (let key of Object.keys(obj)) {
yield [key, obj[key]];
}
}
// an alternative version using a generator expression
function entries(obj) {
return (for (key of Object.keys(obj)) [key, obj[key]]);
}
for (let [key, value] of entries(myObj)) {
// do something with key|value
}
```
Currently, there is no default Object.prototype.@@iterator, so
for-of'ing over an object throws a TypeError which isn't really a
useful default.
No having a default @@iterator also makes that Map({a:1, b:2})
throws which is unfortunate.
Should what you just wrote be made the default
Object.prototype.@@iterator? It is compatible with the signature
the Map constructor expects too.
David
___
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
Re: ES6 iteration over object values
On Sat, Mar 15, 2014 at 5:19 PM, David Bruant bruan...@gmail.com wrote:
Even if error prone, I'd be interested to hear about arguments in the sense
that the risk outweighs the benefits. Iterable-by-default objects is a nice
battery included feature.
I'm pretty sure es-discuss has been over this, but it doesn't hurt to restate:
1. This would mean that evolving any object in any API from *not*
having an @@iterator method to providing its own @@iterator method
would be a backward compatibility risk. Existing code might be using
the default @@iterator to enumerate the object's properties.
2. The default Object.prototype.@@iterator would not appear on
Object.create(null), so the one kind of object people would most want
to have this behavior (Objects specifically created for use as
dictionaries) would be the only kind of object that wouldn't have it.
A separate function would be better—you could apply it to anything
with properties.
Either reason alone would be enough, but to me #1 is a killer.
Platform evolution hazards are bad news. You get stuff like
Array.prototype.values being backed out of browsers, and then you get
stuff like @@unscopables.
I'd like to see an Object.entries method, and Object.values for
completeness. Same visibility rules as Object.keys.
for (let [k, v] of Object.entries(myObj)) {
// do something with k and v
}
-j
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
This thread's original question is answered by the Dict API ( https://github.com/rwaldron/tc39-notes/blob/master/es6/2012-11/nov-29.md#conclusionresolution-5 ). (more inline below) On Sat, Mar 15, 2014 at 6:19 PM, David Bruant bruan...@gmail.com wrote: Le 15/03/2014 22:51, C. Scott Ananian a écrit : It would be nicer to add an Object.entries() method that would return that iterator. Object.prototype.entries or Object.entries(obj)? That would be less error prone than adding a default iterator to every object. The world has survived for-in and its weirdo unchangeable enumerable+proto-climbing rules and that was error prone. Now we can control enumerability of things that are added to the prototype and the proposed default-but-still-overridable semantics is to iterate only over own properties. It's less clear to me that the proposed semantics is error prone. The world has also evolved to a point where tooling can be written to warn about non-overridden @@iterable property for a given class (I feel like it is something TypeScript could do at least). Even if error prone, I'd be interested to hear about arguments in the sense that the risk outweighs the benefits. An @@iterator on Object.prototype would result in Function, Boolean, Date, Error (and friends), and RegExp, having it in their prototype chain--none of these objects have anything to produce as an iterator value. Rick ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
Jason Orendorff wrote:
I'd like to see an Object.entries method, and Object.values for
completeness. Same visibility rules as Object.keys.
for (let [k, v] of Object.entries(myObj)) {
// do something with k and v
}
+1, or +2 counting static methods :-).
/be
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
On Sat, Mar 15, 2014 at 7:38 PM, Jason Orendorff
jason.orendo...@gmail.comwrote:
On Sat, Mar 15, 2014 at 5:19 PM, David Bruant bruan...@gmail.com wrote:
Even if error prone, I'd be interested to hear about arguments in the
sense
that the risk outweighs the benefits. Iterable-by-default objects is a
nice
battery included feature.
I'm pretty sure es-discuss has been over this, but it doesn't hurt to
restate:
1. This would mean that evolving any object in any API from *not*
having an @@iterator method to providing its own @@iterator method
would be a backward compatibility risk. Existing code might be using
the default @@iterator to enumerate the object's properties.
2. The default Object.prototype.@@iterator would not appear on
Object.create(null), so the one kind of object people would most want
to have this behavior (Objects specifically created for use as
dictionaries) would be the only kind of object that wouldn't have it.
A separate function would be better--you could apply it to anything
with properties.
Either reason alone would be enough, but to me #1 is a killer.
Platform evolution hazards are bad news. You get stuff like
Array.prototype.values being backed out of browsers, and then you get
stuff like @@unscopables.
I'd like to see an Object.entries method, and Object.values for
completeness. Same visibility rules as Object.keys.
for (let [k, v] of Object.entries(myObj)) {
// do something with k and v
}
Very enthusiastically agree--these would be excellent additions that balance
nicely with Dict (null __proto_ b/w keys, values, entries), along with all
of the builts-ins that received keys, values and entries on their
prototypes in ES6.
Rick
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
On Sat, Mar 15, 2014 at 6:19 PM, David Bruant bruan...@gmail.com wrote:
Le 15/03/2014 22:51, C. Scott Ananian a écrit :
It would be nicer to add an Object.entries() method that would return that
iterator.
Object.prototype.entries or Object.entries(obj)?
`Object.entries(obj)` and `Object.values(obj)` (as suggested by Jason).
The linked resolution for `Dict`
(https://github.com/rwaldron/tc39-notes/blob/master/es6/2012-11/nov-29.md#conclusionresolution-5)
was less than clear, but generic `Dict.keys(obj)`,
`Dict.entries(obj)`, and `Dict.values(obj)` which can take arbitrary
objects (not just objects with no prototype) would be an okay
fallback. It leaves `Object.keys` an orphan, alas.
`Dict.prototype.entries.call(obj)` would be too long to be useful (but
I don't think that was being proposed).
```js
for (let [key, value] of Dict.entries(myObj)) {
// do something with key|value
}
```
That's not too bad. Shorter than `Object.entries`, even. (But I
personally don't see the point of `new Dict()` instead of
`Object.create(null)`, and prefer the `Object.*` names.)
--scott
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
Re: ES6 iteration over object values
On 3/14/2014 5:16 PM, Mark Volkmann wrote:
Does ES6 add any new ways to iterate over the values in an object?
I've done a lot of searching, but haven't seen anything.
I'm wondering if there is something more elegant than this:
Object.keys(myObj).forEach(function (key) {
let obj = myObj[key];
// do something with obj
});
Not built in, but ES6 does provide a better story for this using
generators and for-of:
```js
// using a generator function
function* entries(obj) {
for (let key of Object.keys(obj)) {
yield [key, obj[key]];
}
}
// an alternative version using a generator expression
function entries(obj) {
return (for (key of Object.keys(obj)) [key, obj[key]]);
}
for (let [key, value] of entries(myObj)) {
// do something with key|value
}
```
___
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
