What are the differences between Map and WeakMap in JavaScript?

What are the differences between Map and WeakMap in JavaScript?

Both Map and WeakMap are collections for storing key-value pairs, but they have some key differences. Map holds strong references to its keys, while WeakMap holds weak references. This means that if there are no other references to a key in a WeakMap, it can be garbage collected.

Can you explain what that means for memory management?

Sure! Since WeakMap allows keys to be garbage collected when there are no other references, it helps prevent memory leaks. This is particularly useful for caching or storing metadata without preventing the keys from being cleaned up.

Are there any limitations to using WeakMap?

Yes, WeakMap only accepts objects as keys, and you cannot iterate over its entries or get its size. This makes it less versatile than Map, but it’s great for specific use cases.

When should I use Map instead of WeakMap?

Use Map when you need to store primitive keys, require iteration, or need to keep track of the size. WeakMap is better for cases where you want to avoid memory leaks with object keys.