ecmascript 6 - JavaScript weak maps - shouldn't it be showing empty?

Question

As I understand it, with JavaScript weak maps, when an object used as a key has no remaining references to it, it is garbage collected (or at least slated for garbage collection) and removed from the weak map.

Quoting from javascript.info (emphasis mine):

If we use an object as the key in [the weak map], and there are no other references to that object – it will be removed from memory (and from the map) automatically.

However, if I run:

const mymap = new WeakMap();
let myobj = {foo: 'bar'};
mymap.set(myobj, 'etc');
myobj = null;
console.log(mymap);
setTimeout(() => console.log(mymap), 1000); //in case garbage collection is delayed

...when inspected in the console, it still shows the single entry I inserted into it.

Now, I realise there's no programmatical way to retrieve this entry, since I no longer have a reference to the object (and weak maps are not enumerable). But why would I believe it's been removed from the map if the console's still showing it's in there?

Answer 1

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