Return value of mutation methods on collections

Claude Pache claude.pache at
Tue Sep 23 13:50:37 PDT 2014

Le 23 sept. 2014 à 22:33, Tab Atkins Jr. <jackalmage at> a écrit :

> On Tue, Sep 23, 2014 at 12:57 PM, Claude Pache <claude.pache at> wrote:
>> Hi,
>> Currently, `(Weak)Map.prototype.set` and `(Weak)Set.prototype.add` are specified to return the collection on which the method is applied.
>> It seems logical to extend that scheme to other mutation methods, namely `.delete()` and `.clear()`.
> .delete() returns a bool for whether it deleted something; it's not a
> void return type which can be usefully set to the collection instead.
> ~TJ

Is the current `.delete()` return value more useful than the proposed one?

Anyway, I thought more about consistency than about usefulness; because for each method, there are several potentially useful return values. (For example, the `.set()` and `.add()` methods could arguably return the value just set/added, just like ` = value` is `value`, or `foo.appendChild(node)` is `node`, which I find both positively useful in practice.)


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