847355 - Add intersections and unions to Set (and Map)

Status: RESOLVED DUPLICATE of bug 1805038

(Core :: JavaScript Engine, enhancement)

Description

[aleth [:aleth]]

It would be useful to be able to form the intersection and the union of two Sets.

The union would be similar to Array.concat, while an intersection is similar to a particular Array.filter (so it may also make sense to have filter for Sets instead).

I don't know if this has been proposed already, but it is not part of the Harmony specs (http://wiki.ecmascript.org/doku.php?id=harmony:simple_maps_and_sets).

Comment 1

[Till Schneidereit [:till]]

As these methods don't seem to be part of any proposal yet, you should propose them on the es-discuss mailing list.

Comment 2

[KOLANICH]

Why only intersections and unions? How about complements and other set operations?

Comment 3

[aleth [:aleth]]

(In reply to Till Schneidereit [:till] from comment #1)
> As these methods don't seem to be part of any proposal yet, you should
> propose them on the es-discuss mailing list.

For future reference, I proposed this on es-discuss in this thread https://mail.mozilla.org/pipermail/es-discuss/2013-March/028963.html. Some favourable discussion followed, which as far as I know didn't get taken up in a proposal however.