What are some examples of WeakMaps in JavaScript?

Can you explain what a WeakMap is in JavaScript?

Sure! A WeakMap is a collection of key-value pairs where the keys are objects and the values can be any value. The keys are weakly referenced, meaning they can be garbage collected if there are no other references to them.

What are some practical examples of using WeakMaps?

One common use case is to store private data for objects. For instance, you can use a WeakMap to associate private properties with an object without exposing them directly.

Can you show me a code example?

Absolutely! Here's a simple example:

const privateData = new WeakMap();

class User {
    constructor(name) {
        privateData.set(this, { name });
    }
    getName() {
        return privateData.get(this).name;
    }
}

const user = new User('Alice');
console.log(user.getName()); // Alice

Are there any limitations to using WeakMaps?

Yes, WeakMaps only accept objects as keys, and you cannot iterate over them or get their size. This makes them less versatile than regular Maps.