Node.js · Senior · Question 8 of 75

What are `WeakRef` and `FinalizationRegistry` NOT good for?

1Caches that may drop entries when memory is needed
2Optional cleanup of native memory as a safety net
✓Correct answer: Releasing important resources such as file handles or DB connections at a predictable time

Explanation

Garbage collection timing is not guaranteed, and finalizers may never run. Release resources explicitly with close() or using/Symbol.dispose.

Further reading

Node.js Learn: Memory diagnostics ↗

Test yourself

Take the Node.js · Senior quiz: questions and options are shuffled, and you get a review of your mistakes at the end.