Hey all,
I'd like to have something like a WeakMap where the keys can be primitives
and the values are weakly-held Objects, so if there are no more references
to any of the Object values that the entry gets removed from the map.
For example, it might look like this:
```
{
["foo"] => SomeObject,
["
bar
"] =>
OtherObject
,
}
```
where if there are no more references to `OtherObject`, then `['bar'] =>
OtherObject` is removed from the map.
Usage would be very similar to WeakMap, like
```
let m = new ReversedWeakMap
m.add('foo', SomeObject)
m.add('
bar
',
OtherObject
)
console.log(m.get('bar')) // OtherObject
... time passes, no more references to OtherObject, OtherObject is
collected ...
console.log(m.get('bar')) // undefined
```
I thought of using WeakMap values as keys, and vice versa, but it seems to
be impossible.
I guess maybe it is difficult to add this natively because it would mean
that GC needs to be completely deterministic as far as JS programs go. For
example:
```js
let m = new ReversedWeakMap
function main() {
m.set('foo', {})
console.log(m.get('foo')) // {}
}()
main()
// GC would have to be guaranteed to have happened at this point.
console.log(m.get('foo')) // undefined
```
*/#!/*JoePea
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