Answer
Keys help React correctly match elements during reconciliation. Unstable keys cause incorrect state retention or DOM mismatches.
Quick Answer
Stable keys let React match components between renders — the same key on the same item means React reuses its DOM node and state. Unstable keys (like Math.random()) cause React to destroy and recreate components every render — losing state and causing flicker. Keys must be unique among siblings, not globally.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ