What JS needs is a [cascade
operator](https://esdiscuss.org/topic/cascade-operator). With this operator,
property accessors and methods can be effectively chained without requiring
methods to return `this`.
___
es-discuss mailing list
If one thing this is clear from this discussion, it is that different
programmers have different preferences (perhaps even changeable
depending on use case). So, no single standard API will suit everyone
and the language support for different patterns could be improved.
Meanwhile, it seems one
On 6 December 2012 18:38, Rick Waldron waldron.r...@gmail.com wrote:
I agree with other voices in this thread that in general, returning
'this' rather is an anti pattern.
The evidence I've brought to this discussion shows that the most widely used
and depended upon libraries heavily favor the
Andreas Rossberg wrote:
On 6 December 2012 18:38, Rick Waldronwaldron.r...@gmail.com wrote:
I agree with other voices in this thread that in general, returning
'this' rather is an anti pattern.
The evidence I've brought to this discussion shows that the most widely used
and depended upon
On Wed, Dec 5, 2012 at 10:43 PM, Rick Waldron waldron.r...@gmail.comwrote:
On Wed, Dec 5, 2012 at 3:26 PM, Domenic Denicola
dome...@domenicdenicola.com wrote:
Readability or library preference aside, I still think it's bizarre that
map.set(key, val)
is analogous to
(dict[key] = val,
On 6 December 2012 05:05, Rick Waldron waldron.r...@gmail.com wrote:
Again, I reject the notion that someone might screw up is a valid argument
for this, or any, discussion. It's one thing to be aware of the potential
for misuse, but entirely another to succumb to fear driven design.
Fear
On Wed, Dec 5, 2012 at 8:05 PM, Rick Waldron waldron.r...@gmail.com wrote:
On Wed, Dec 5, 2012 at 10:33 PM, Bill Frantz fra...@pwpconsult.com wrote:
On 12/5/12 at 1:50 AM, jussi.kallioko...@gmail.com (Jussi Kalliokoski)
wrote:
I personally think returning `this` in absence of any
On Thu, Dec 6, 2012 at 3:48 AM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
And if it comes down to precedents in the language, even Array#forEach()
returns undefined, contrary to popular libraries out there. Let's keep some
consistency here.
Array.prototype.map and
On Thu, Dec 6, 2012 at 6:53 AM, Andreas Rossberg rossb...@google.comwrote:
On 6 December 2012 05:05, Rick Waldron waldron.r...@gmail.com wrote:
Again, I reject the notion that someone might screw up is a valid
argument
for this, or any, discussion. It's one thing to be aware of the
On Thu, Dec 6, 2012 at 10:34 AM, Mark S. Miller erig...@google.com wrote:
Is fear driven design just a derogatory phrase for defensive
programming?
Not at all.
I wrote fear driven design in a moment of frustration, referring only to
the opposition of adopting a (widely held as) best
On Thu, Dec 6, 2012 at 8:25 PM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
On Thu, Dec 6, 2012 at 7:32 PM, Rick Waldron waldron.r...@gmail.comwrote:
Array.prototype.map and Array.prototype.filter return newly created
arrays and as such, are chainable (and will have the same
On Thu, Dec 6, 2012 at 8:44 PM, Rick Waldron waldron.r...@gmail.com wrote:
values() returns an iterable of the values in the array. Array, Map and
Set will receive all three: keys(), values(), entries(). Feel free to start
a new thread if you want to argue about iterator protocol.
Yes, I
On Thu, Dec 6, 2012 at 2:41 PM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
On Thu, Dec 6, 2012 at 8:44 PM, Rick Waldron waldron.r...@gmail.comwrote:
values() returns an iterable of the values in the array. Array, Map and
Set will receive all three: keys(), values(), entries(). Feel
Had same thoughts on returning true or false as map.delete(key) would do.
However, it's easy to have ambiguity there ... assuming the key can always
be set, 'cause even a frozen Map should be able, and it is, to set a key
internally, will true mean that key was not there ? will false mean that
Andrea Giammarchi wrote:
Anyway, I would like to know what other TC39 members think, cause they
all agreed already
You've heard from Mark and me (also Jason Orendorff of Mozilla, who is
de-facto champion of some ES6 proposals) in this thread, along with
Rick. You won't get a definitive
My 2 cents against the windmills...
I personally think returning `this` in absence of any meaningful value (and
chaining in general) is a bad pattern. Chaining leads to worse readability
(there's nothing subjective about this, if you have to scan the code to
another page to figure out which
Date: Tue, 4 Dec 2012 11:03:57 -0800
From: bren...@mozilla.org
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
Allen Wirfs-Brock wrote:
It's less clear which is the best choice for JS.
Cascading wants its own special form, e.g., Dave's
mustache-repurposed proposal at
https
On Wed, Dec 5, 2012 at 10:06 AM, Nathan Wall nathan.w...@live.com wrote:
Date: Tue, 4 Dec 2012 11:03:57 -0800
From: bren...@mozilla.org
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
Allen Wirfs-Brock wrote:
It's less clear which is the best choice for JS.
Cascading wants
AM, Nathan Wall
nathan.w...@live.comjavascript:_e({}, 'cvml', 'nathan.w...@live.com');
wrote:
Date: Tue, 4 Dec 2012 11:03:57 -0800
From: bren...@mozilla.org javascript:_e({}, 'cvml',
'bren...@mozilla.org');
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
Allen Wirfs-Brock
with that
knowledge, but we don't necessarily have to follow the norm.
Cheers,
Jussi
On Wednesday, December 5, 2012, Rick Waldron wrote:
On Wed, Dec 5, 2012 at 10:06 AM, Nathan Wall nathan.w...@live.comwrote:
Date: Tue, 4 Dec 2012 11:03:57 -0800
From: bren...@mozilla.org
Subject: Re: (Map|Set
11:03:57 -0800
From: bren...@mozilla.org
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
Allen Wirfs-Brock wrote:
It's less clear which is the best choice for JS.
Cascading wants its own special form, e.g., Dave's
mustache-repurposed proposal at
https://blog.mozilla.org
On Wed, Dec 5, 2012 at 8:52 AM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
and as last argument from my side, I **LOVE** the DOM appendChild method and
I use it a lot
var div = document.body.appendChild(document.createElement(div));
This is the best example of returning the value I
nathan.w...@live.comwrote:
Date: Tue, 4 Dec 2012 11:03:57 -0800
From: bren...@mozilla.org
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
Allen Wirfs-Brock wrote:
It's less clear which is the best choice for JS.
Cascading wants its own special form, e.g., Dave's
mustache
nope
el.appendChild(document.createElement(another)).parentNode.appendChild(document.createElement(another))
... etc
the way I use it is to add and address ... once again
var current = el.firstChild ||
el.appenChild(document.createElement(first));
^_^
On Wed, Dec 5, 2012 at 9:26 AM, Tab
On Wed, Dec 5, 2012 at 1:50 AM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
My 2 cents against the windmills...
I personally think returning `this` in absence of any meaningful value (and
chaining in general) is a bad pattern. Chaining leads to worse readability
(there's nothing
Dart has a cascade operator (..) [1]. That's the Right Way to do chaining.
We should watch how it goes in Dart before prematurely committing to this
iffy simulation of cascading at the API level.
- Kevin
[1]
On Wed, Dec 5, 2012 at 1:04 PM, Mark S. Miller erig...@google.com wrote:
On Wed, Dec 5, 2012 at 1:50 AM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
My 2 cents against the windmills...
I personally think returning `this` in absence of any meaningful value
(and
chaining in
let's summarize then:
1. ~Weak/Map#set and Set#add returns void
1.1 void as return is considered useless
2. cahinability looks like the most common pattern so those methods
should return `this`
2.1 example: return map.has(key) ? map.get(key) : map.set(key,
operation()).get(key);
forgot latter comparison with an unknown value
get the value
void: var v = generate(); map.set(key, v); return v;
this: return map.set(key, generate()).get(key);
value: return map.set(key, generate());
br
___
es-discuss mailing list
On Wed, Dec 5, 2012 at 10:04 AM, Mark S. Miller erig...@google.com wrote:
On Wed, Dec 5, 2012 at 1:50 AM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
My 2 cents against the windmills...
I personally think returning `this` in absence of any meaningful value (and
chaining in general)
I think here you have more libraries authors than users, with daily basis
tasks to solve without jQuery and others ... that's why here things are
different from out there, is not about knowing more or anything, IMHO.
Said that, since as I have written no pattern blocks anyone to reach same
goals
On Wed, Dec 5, 2012 at 2:02 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
let's summarize then:
1. ~Weak/Map#set and Set#add returns void
1.1 void as return is considered useless
2. cahinability looks like the most common pattern so those methods
should return `this`
05, 2012 14:57
To: Mark S. Miller
Cc: es-discuss@mozilla.org
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
On Wed, Dec 5, 2012 at 10:04 AM, Mark S. Miller erig...@google.com wrote:
On Wed, Dec 5, 2012 at 1:50 AM, Jussi Kalliokoski
jussi.kallioko...@gmail.com wrote:
My 2 cents against
On Wed, Dec 5, 2012 at 3:13 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
Said that, since as I have written no pattern blocks anyone to reach
same goals inline I don't even feel that strong about it, I am just saying
what would be the ideal scenario in my opinion, wondering
On Wed, Dec 5, 2012 at 3:26 PM, Domenic Denicola
dome...@domenicdenicola.com wrote:
Readability or library preference aside, I still think it's bizarre that
map.set(key, val)
is analogous to
(dict[key] = val, dict)
and not to
dict[key] = val
When I'm using a fluent library like
I never said they made a decision without valid considerations, I am saying
I haven't seen any informal survey **here**, the place where theoretically
we discuss ECMAScript and its present and future.
I want believe it makes sense to keep discussing here, as it has always
been, and I don't want
On Wed, Dec 5, 2012 at 3:55 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
I never said they made a decision without valid considerations, I am
saying I haven't seen any informal survey **here**, the place where
theoretically we discuss ECMAScript and its present and future.
I've
It does not matter what Map.prototype.set returns. Almost all call sites
will ignore the return value, just like they do in every other language.
If (like me) you have strong feelings about this that are not backed by
much more than personal taste, I suggest a brisk walk. That's what I'll be
On 12/5/12 at 1:50 AM, jussi.kallioko...@gmail.com (Jussi
Kalliokoski) wrote:
I personally think returning `this` in absence of any meaningful value (and
chaining in general) is a bad pattern.
/lurk
I have to agree with Jussi here. Whenever I consider chaining
using the returned values
On Wed, Dec 5, 2012 at 10:33 PM, Bill Frantz fra...@pwpconsult.com wrote:
On 12/5/12 at 1:50 AM, jussi.kallioko...@gmail.com (Jussi Kalliokoski)
wrote:
I personally think returning `this` in absence of any meaningful value
(and
chaining in general) is a bad pattern.
/lurk
I have to
Nathan
Date: Mon, 3 Dec 2012 14:21:24 -0800
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
From: andrea.giammar...@gmail.com
To: waldron.r...@gmail.com
CC: es-discuss@mozilla.org
IMHO, a set(key, value) should return the value as it is when you address a
value
var o
--
Date: Mon, 3 Dec 2012 14:21:24 -0800
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
From: andrea.giammar...@gmail.com
To: waldron.r...@gmail.com
CC: es-discuss@mozilla.org
IMHO, a set(key, value) should return the value as it is when you address
a value
var o = m.get(k) || m.set(k
Allen Wirfs-Brock wrote:
It's less clear which is the best choice for JS.
I have to say I think Mark is on the better track (not to say only
right track). Cascading wants its own special form, e.g., Dave's
mustache-repurposed proposal at
On Tue, Dec 4, 2012 at 1:55 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
clear for us ( Developers ) but also clear semantically speaking.
As it is proposed now it looks like if a setter returns something which
is the context while, again, when you set 99% of the time you don't
for develoeprs I meant jQuery users too, being one of th emost popular API
out there.
What I meant with jQuery#add method is that last thing added is the one
returned, it does nto return the initial object, it returns the new result
out of a merge but this is not the initial this, this is a new
it would be nice to add a #put(key, value) that returns value and see what
developers prefer on daily basis tasks :-)
anyway, if it won't change, it's OK, I had my answer, thanks
On Tue, Dec 4, 2012 at 12:03 PM, Rick Waldron waldron.r...@gmail.comwrote:
On Tue, Dec 4, 2012 at 2:46 PM,
On Tue, Dec 4, 2012 at 3:07 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
it would be nice to add a #put(key, value) that returns value and see what
developers prefer on daily basis tasks :-)
anyway, if it won't change, it's OK, I had my answer, thanks
I like surveying actual
The survey I'd like to see is among underscore, jQuery, and other
popular libraries (go by NPM dependency frequency and client-side use
frequency), how do set-like methods work: return-this or return-v?
This is closer than a people-survey to mapping the cowpath.
/be
agreed ... but then these analysis should be done before making decisions
in TC39 meeting notes.
If this was the case then, as I have said, I am OK with the decision ( de
gustibus )
br
On Tue, Dec 4, 2012 at 12:50 PM, Brendan Eich bren...@mozilla.org wrote:
The survey I'd like to see is
On Tue, Dec 4, 2012 at 3:50 PM, Brendan Eich bren...@mozilla.org wrote:
The survey I'd like to see is among underscore, jQuery, and other popular
libraries (go by NPM dependency frequency and client-side use frequency),
how do set-like methods work: return-this or return-v?
underscore and
On Mon, Dec 3, 2012 at 2:21 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
IMHO, a set(key, value) should return the value as it is when you address a
value
var o = m.get(k) || m.set(k, v); // o === v
// equivalent of
var o = m[k] || (m[k] = v); // o === v
If this pattern is
as discussed before, the problem with setDefault() approach you are
suggesting is that the dict(), at least in JS, will be created in any case.
var newDict = a.setDefault(k1, dict());
above operation will invoke dict() regardless k1 was present or less and
this is not good for anyone: RAM, CPU,
On Mon, Dec 3, 2012 at 4:28 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
I wonder what was the use case that convinced TC39 to return `this` with
these methods.
Assuming you read the notes, I proposed the agenda item based on the best
practice of ensuring meaningful returns, and
IMHO, a set(key, value) should return the value as it is when you address a
value
var o = m.get(k) || m.set(k, v); // o === v
// equivalent of
var o = m[k] || (m[k] = v); // o === v
a set with a key that returns `this` is a non case so almost as useless as
the void return is.
Usefulness comes
On Mon, Dec 3, 2012 at 5:21 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
IMHO, a set(key, value) should return the value as it is when you address
a value
var o = m.get(k) || m.set(k, v); // o === v
// equivalent of
var o = m[k] || (m[k] = v); // o === v
a set with a key
fair enough ... but here there was a typo, right?
set.add( value ).forEach( item = ...send to some operation );
Thanks
On Mon, Dec 3, 2012 at 2:44 PM, Rick Waldron waldron.r...@gmail.com wrote:
On Mon, Dec 3, 2012 at 5:21 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
Date: Mon, 3 Dec 2012 14:21:24 -0800
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
From: andrea.giammar...@gmail.com
To: waldron.r...@gmail.com
CC: es-discuss@mozilla.org
IMHO, a set(key, value) should return the value as it is when you address a
value
var o = m.get(k) || m.set(k, v
On Mon, Dec 3, 2012 at 5:49 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
fair enough ... but here there was a typo, right?
set.add( value ).forEach( item = ...send to some operation );
Possibly? s/item/value/ ?
Rick
Thanks
On Mon, Dec 3, 2012 at 2:44 PM, Rick
I meant the forEach on a Set which I've never seen before in specs ... ;-)
On Mon, Dec 3, 2012 at 2:54 PM, Rick Waldron waldron.r...@gmail.com wrote:
On Mon, Dec 3, 2012 at 5:49 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
fair enough ... but here there was a typo, right?
Andrea's use case (m.get(k) ||
m.set(k, v)) more compelling than the method chaining possibilities.
Nathan
--
Date: Mon, 3 Dec 2012 14:21:24 -0800
Subject: Re: (Map|Set|WeakMap)#set() returns `this` ?
From: andrea.giammar...@gmail.com
To: waldron.r...@gmail.com
CC
On Mon, Dec 3, 2012 at 5:55 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
I meant the forEach on a Set which I've never seen before in specs ... ;-)
Set and Map both have a forEach method (since rev10 I believe, 15.16.5.5
and 15.14.5.4 respectively)
Rick
crap ... this stuff is not in V8 thought, not in node --harmony at least
... I need to update my polyfills .. !
On Mon, Dec 3, 2012 at 3:05 PM, Rick Waldron waldron.r...@gmail.com wrote:
On Mon, Dec 3, 2012 at 5:55 PM, Andrea Giammarchi
andrea.giammar...@gmail.com wrote:
I meant the
Subject: RE: (Map|Set|WeakMap)#set() returns `this` ?
I'm not a person of influence, but as a JS developer, I agree with Andrea on
this. I think Map#set() should return the value. I would expect the same
behavior as obj[key] = value. I find Andrea's use case (m.get(k) || m.set(k,
v)) more
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