839979 - Implement Object.is

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[David Bruant]

Per TC39 January 2013 meeting [1], is/isnt are out as operators, but Object.is remains (no need for Object.isnt, ! is enough for negation)

[1] https://github.com/rwldrn/tc39-notes/blob/master/es6/2013-01/jan-29.md#41-isisnt-operators

Comment 1

[Tom S [:evilpie]]

I implemented these as |is| and |isnt| before, taking.

Comment 2

[Tom S [:evilpie]]

Attachment: v1

I took some ideas for tests from bug 715359. The rest is pretty straight forward, except maybe the args.length() < 2, because this is actually not clearly defined. So I made a post to es-discuss.

Comment 3

[Tom S [:evilpie]]

For some reason I confused myself more than I should have here. The args.length() < 2 should not return false here. New patch coming up.

Comment 4

[Tom S [:evilpie]]

Attachment: v2

This now has the right behavior.

Comment 5

[Jason Orendorff [:jorendorff]]

Comment on attachment 725938 [details] [diff] [review]
v2

Review of attachment 725938 [details] [diff] [review]:
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Beautiful!

Comment 6

[Tom S [:evilpie]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a321bf04c39b

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/a321bf04c39b

Comment 8

[Tom S [:evilpie]]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
https://developer.mozilla.org/en-US/docs/Web/JavaScript/ECMAScript_6_support_in_Mozilla
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/22