React · Junior · Question 60 of 75

Must `key` values be unique across the whole app?

✓Correct answer: No - only among siblings in the same list
2Yes, globally unique like DOM ids
3Yes, within the whole component

Explanation

Two different lists can reuse the same ids as keys. key isn't passed to the component as a prop; pass the id separately if the child needs it.

Further reading

react.dev: Rendering Lists ↗

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