What are the differences between WeakMaps and regular Maps in JavaScript?

What are the differences between WeakMaps and regular Maps in JavaScript?

WeakMaps and regular Maps are both key-value data structures in JavaScript, but they have some key differences. WeakMaps hold weak references to their keys, meaning that if there are no other references to a key, it can be garbage collected. This is not the case with regular Maps, which hold strong references to their keys.

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

Sure! You might use a WeakMap when you want to associate data with DOM elements without preventing those elements from being garbage collected. For instance, if you want to store metadata about a DOM node, using a WeakMap allows the node to be cleaned up when it's removed from the document.

Are there any performance differences between the two?

Yes, WeakMaps can be more memory efficient in certain scenarios because they allow for garbage collection of keys that are no longer needed. Regular Maps, on the other hand, can lead to memory leaks if you forget to remove keys.

What are the limitations of WeakMaps?

WeakMaps have some limitations: their keys must be objects, and you cannot iterate over them or get their size. This makes them less versatile than regular Maps, which can hold any type of key and provide more functionality.