useCallback and useMemo are both hooks provided by React to optimize performance in functional components by memoizing values. While they serve similar purposes, they are used in different scenarios:
- "useCallback" is primarily used to memoize functions. It returns a memoized version of the callback function that only changes if one of the dependencies has changed.
- It's useful when passing callbacks to child components that rely on reference equality to prevent unnecessary re-renders.
- Syntax: const memoizedCallback = useCallback(callback, dependencies)
- "useMemo" is used to memoize the result of a function call. It re-computes the memoized value when one of the dependencies has changed.
- It's useful for optimizing expensive computations or calculations that are not related to rendering.
- Syntax: const memoizedValue = useMemo(() => computeExpensiveValue(a, b), [a, b])