On Thu, Sep 10, 2015 at 11:02 AM, Michael McGlothlin <mike.mcgloth...@gmail.com> wrote: > One issue I did notice with WeakMaps is that because it can't use primative > values as keys that they'll throw errors unless otherwise handled. Checking > if they are an instanceof Object and if not using a Map instead seems to work. > > I wouldn't think using primatives as WeakMap keys would be an issue.
Primitives have no notion of "reference" or "liveness". They can and are destroyed and recreated all the time, or shared across multiple independent non-communicating contexts. As such, they aren't a reliable key for WeakMaps, which keep their value alive "as long as the key is alive". Using a primitive string as a key can inadvertently leak the value for a long time, as the key might be interned and long-lived, far past the point when your code has dropped the intended references to it. ~TJ _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
