What is the difference between useCallback and useMemo?

useCallback and useMemo are React hooks that help optimize performance by preventing unnecessary re-creations of functions and computations.

• useCallback returns a memoized version of the function that is preserved between renders if dependencies haven't changed. This is useful when passing a function to a child component to avoid unnecessary re-renders.

• useMemo returns a memoized value computed by a function and recalculates it only when dependencies change. It is used to optimize expensive calculations.

Example:

const memoizedCallback = useCallback(() => {
  doSomething(a, b);
}, [a, b]);

const memoizedValue = useMemo(() => computeExpensiveValue(a, b), [a, b]);

Thus, useCallback memoizes the function, and useMemo memoizes the result of a computation.