Actually, those are not sufficient to implement weak references, and have a much different use case! With WeakMap and WeakSet, the <i>keys</i> are weakly referenced, hence the names. If you have a WeakMap, you can&#x27;t produce a value stored in the map without a strong reference to a key.<p>You can actually polyfill WeakMap and WeakSet. You can&#x27;t do the same for weak references.