How would you explain memo, useMemo, useCallback to a junior engineer?

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Quick interview answer

Explain memo, useMemo, useCallback in one sentence, then a tiny example, then one “don’t do this” tip. React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders.

Detailed answer

Junior-friendly explanation of memo, useMemo, useCallback: Plain English: React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders. Tiny example: Heavy DataGrid row component wrapped in memo; stable onSort callback via useCallback. One warning: Memoizing everything; useCallback with empty deps capturing changing state.

Full explanation

Keep jargon low, then layer detail. React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders.

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Parent context — memo, useMemo, useCallback

React.memo skips re-render if props shallow-equal. useMemo caches computed value; useCallback caches function reference — helps memoized children avoid redundant renders.

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