[peanut_worm]

What does storing the state as a WeakMap do here?

[atirip]

I initially just mimicked the React version into Vanilla, so this was a show-off how to do that somewhat exactly the same way. But in this particular case it serves no meaning, we can always read 'checked' from DOM.

[Ndymium]

If the custom DOM element is deleted, then its entry in the map will also be deleted. Otherwise it would hang around in the Map forever (unless manually deleted in a lifecycle callback).

[azangru]

Why would component's state sit outside the component anyway? Why isn't it a field on the extended class?

[Ndymium]

True, it would make more sense to do that.