807001 - Map.prototype.size and Set.prototype.size should be accessor properties

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jason Orendorff [:jorendorff]]

This is a breaking change for any code using .size() on Map or Set objects. The patch includes fixes for in-tree uses.

Comment 1

[Jason Orendorff [:jorendorff]]

Attachment: v1

I considered changing JS_DefineProperty with JSPROP_NATIVE_ACCESSORS so as to make the getter function objects have getter.name == "size", but function object .name properties are totally unspecified. Some other time perhaps.

Comment 2

[Jeff Walden [:Waldo]]

Comment on attachment 676658 [details] [diff] [review]
v1

Review of attachment 676658 [details] [diff] [review]:
-----------------------------------------------------------------

Given that the accessors in { get foo() { } } have no name, and perhaps we might want to self-host this or something at some point, it seems best to not have a name, definitely.

I completely agree with the logical argument for .size over .size(), as made in the es-discuss thread; it's totally rational and correct, and we should have .size, not .size().  But when I look at this, this irrationally looks weird and wrong to me.  Maybe it's just because I'm seeing both cases next to each other and there's cross-pollination of smell.  I dunno.  Forward!

Comment 3

[Jason Orendorff [:jorendorff]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/47711ed9454d

Comment 4

[Gregory Szorc [:gps]]

Please update MDN:

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Map
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Set

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/47711ed9454d

Comment 6

[Mark Hammond [:markh] [:mhammond]]

I just updated the Map and Set documentation, including a note that it changed in FF19

Comment 8

[Tom S [:evilpie]]

Looking at this diff from v8 http://code.google.com/p/v8/source/detail?r=12875, they seem to set the getter name to "size".

Comment 9

[Mark Hammond [:markh] [:mhammond]]

See comment 6 - I updates the docs on MDN (https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Map and https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Set) and cleared dev-doc-needed based on that.  If something else is necessary, please indicate it.

Comment 10

[Kohei Yoshino [:kohei]]

I think this should be mentioned in https://developer.mozilla.org/en-US/docs/Firefox_19_for_developers too.

Comment 11

[Mark Hammond [:markh] [:mhammond]]

(In reply to Kohei Yoshino from comment #10)
> I think this should be mentioned in
> https://developer.mozilla.org/en-US/docs/Firefox_19_for_developers too.

Done :)

Comment 12

[Kohei Yoshino [:kohei]]

Thanks!