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What are WeakMap and WeakSet?

Q: What are WeakMap and WeakSet?

**Core concept (TL;DR).** WeakMap and WeakSet are collections that hold their keys/values **weakly**: entries reference objects without preventing them from being garbage-collected. When the only reference left to an object is inside a WeakMap/WeakSet, it can be reclaimed automatically — preventing memory leaks. Weak references → keys can be garbage-collected key object <path d="M 180 66 L 240 66" fill="n

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