in node 0.10, Map.prototype.forEach.call({}, function () {}) does not throw

[ljharb]

Map#forEach and Set#forEach are supposed to throw a TypeError if their receiver/"this" value is not an actual Map or Set. In node 0.12 and later, with core-js required, it throws as expected, but in node 0.10 and earlier, it does not.

This is preventing is-equal and expect from working with core-js in an environment without native Map and Set, since it gives false positives for object values.

[zloirock]

I saw this issue. I don't think it is a principal behavior for polyfill, but ok, I will add it.

[ljharb]

It's the only reliable way to determine if something is a Map or Set, cross-realm (ie, not relying on instanceof). Thanks!

[mjackson]

👍 Thanks, @zloirock! This is important for feature detection.

[ljharb]

Thanks! Please let me know when you release a v2.0.0

[ljharb]

Any update? I'd love to verify that is-equal works with core-js v2 and higher.

[zloirock]

Any update?

Available 2.0.0-beta.2, I should stabilize a few more things before the final release.

[ljharb]

Great, thanks!

[zloirock]

Available in 2.0.