What are the differences between WeakMap and Map in JavaScript?

What are the differences between WeakMap and Map in JavaScript?

WeakMap and Map are both collections in JavaScript, but they have key differences. WeakMap holds weak references to its keys, meaning if there are no other references to a key, it can be garbage collected. In contrast, Map holds strong references, preventing garbage collection.

Can you explain what that means in practical terms?

Sure! In practical terms, if you use a WeakMap, you can store objects as keys without preventing them from being garbage collected when they are no longer needed. This is useful for memory management. With a Map, the keys will remain in memory as long as the Map exists, which can lead to memory leaks if not managed properly.

Are there any performance differences between the two?

Yes, WeakMap can be more efficient in terms of memory usage since it allows for garbage collection of keys. However, Map may offer better performance for certain operations due to its strong references and predictable behavior.

When should I use WeakMap instead of Map?

You should use WeakMap when you want to associate data with objects without preventing those objects from being garbage collected. It's ideal for scenarios like caching or storing private data.