Weakset

The Set is used to store any type of data such as primitives and object types. Whereas WeakSet is an object to store weakly held objects in a collection. (i.e, WeakSet is the collections of objects only). Here weak means, If no other references to an object stored in the WeakSet exist, those objects can be garbage collected.

let myUserSet = new WeakSet();

let john = { name: "John" };
let rocky = { name: "Rocky" };
let alex = { name: "Alex" };
let nick = { name: "Nick" };

myUserSet.add(john);
myUserSet.add(rocky);
myUserSet.add(john);
myUserSet.add(nick);

console.log(myUserSet.has(john)); // true
console.log(myUserSet.has(alex)); // false
console.log(myUserSet.delete(nick));
console.log(myUserSet.has(nick)); // false

john = null;