I called it a “weak map” rather than “WeakMap” deliberately. Bob was describing what he wanted, not what he got. However, if memory serves, the JS weak map has

I called it a “weak map” rather than “WeakMap” deliberately. Bob was describing what he wanted, not what he got. However, if memory serves, the JS weak map has the semantics bob wanted: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...