Add intersections and unions to Set

David Bruant bruant.d at gmail.com
Tue Mar 5 06:15:03 PST 2013


I agree on the need but forsee problems with parametrized equivalence 
operator [1][2] like "which comparator should be used for the union of 2 
sets with different comparators?"

The need for set intersection/union/minus/etc. feels more important than 
the need to parametrized the comparator.

David

[1] 
https://github.com/rwldrn/tc39-notes/blob/master/es6/2013-01/jan-29.md#43-parameterize-the-equivalence-operator-for-mapset
[2] 
https://github.com/rwldrn/tc39-notes/blob/master/es6/2013-01/jan-31.md#mapset-comparator

Le 04/03/2013 19:08, aleth at instantbird.org a écrit :
> It would be useful to be able to form the intersection and the union of
> two Sets. These are natural operations that are currently not part of
> the API
> (http://wiki.ecmascript.org/doku.php?id=harmony:simple_maps_and_sets).
>
> Similar methods would make sense for Map, but one would have to think
> about what to do in the case where the key but not the value matches.
>
> An intersection is equivalent to a particular filter, so an alternative
> might be to add a method like Array.filter to Sets instead.
>
> (I filed bug 847355 for this and was told this mailing list was the
> right place for this suggestion.)
>



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