Answer
React detects state changes using reference equality. Mutating state directly keeps the same reference, preventing React from re-rendering.
Quick Answer
React uses object identity to detect changes. If you mutate an object in place (array.push, obj.x = 1), the reference doesn't change — React thinks nothing changed and skips re-rendering. Always create new objects/arrays for state updates so React sees a new reference and knows to update the UI.
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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