The WeakSet object lets you store weakly held objects in a collection.
The WeakSet.prototype property represents the prototype for the WeakSet constructor.
The add() method appends a new object to the end of a WeakSet object.
The clear() method used to remove all elements from a WeakSet object, but is no longer part of ECMAScript and its implementations.
The delete() method removes the specified element from a WeakSet object.
The has() method returns a boolean indicating whether an object exists in a WeakSet or not.