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

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

WeakMaps and Maps both store key-value pairs, but WeakMaps have some unique characteristics. WeakMaps allow garbage collection of keys, meaning if there are no other references to the key, it can be removed from memory. This can lead to better memory management in certain scenarios.

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

Sure! Use WeakMap when you want to associate data with DOM elements without preventing them from being garbage collected. For instance, if you want to store metadata about a DOM node, WeakMap is ideal.

Are there any performance benchmarks comparing the two?

Yes, benchmarks often show that Maps can be faster for frequent additions and lookups due to their optimized structure. However, WeakMaps can be more efficient in memory usage when dealing with large datasets that involve DOM elements.

What about the iteration capabilities of both?

Maps are iterable, meaning you can easily loop through their entries. WeakMaps, on the other hand, are not iterable, which can be a limitation if you need to access all entries.