The Map object holds key-value pairs and remembers the original insertion order of the keys. Whereas, the WeakMap object is a collection of key/value pairs in which the keys are weakly referenced. You can use any data type as a key or value in a Map whereas in WeakMap you can only use objects as keys. The WeakMap is not iterable whereas Map is. In WeakMap it holds the weak reference to the original object which means if there are no other references to an object stored in the WeakMap, those objects can be garbage collected.