What are the differences between WeakMaps and Maps in JavaScript?

What are the differences between WeakMaps and Maps in JavaScript?

WeakMaps and Maps are both collections for storing key-value pairs, but they have key differences. WeakMaps hold weak references to keys, meaning if there are no other references to a key, it can be garbage collected. Maps, on the other hand, hold strong references, preventing garbage collection.

Can you give me an example of when to use WeakMap?

Sure! Use WeakMap when you want to associate data with an object without preventing that object from being garbage collected. For instance, if you want to store metadata about DOM elements, WeakMap is ideal because it won't keep the DOM elements in memory if they are removed from the document.

What are the performance implications of using one over the other?

WeakMaps can be more memory efficient since they allow for garbage collection of keys. However, Maps may offer better performance for frequent additions and deletions due to their strong references. The choice depends on your specific use case.

Are there any limitations to using WeakMaps?

Yes, WeakMaps only allow objects as keys, and you cannot iterate over them or get their size. This makes them less versatile than Maps, but they are useful for certain scenarios.