What is useCallback and why is it used?

The useCallback is a React Hook used to memoize function definitions between renders. It returns the same function reference unless its dependencies change. This is especially useful when passing callbacks to optimized child components (e.g. those wrapped in React.memo) to prevent unnecessary re-renders.

Example:

 const handleClick = useCallback(() => {
   console.log('Button clicked');
 }, []);

Without useCallback, a new function is created on every render, potentially causing child components to re-render unnecessarily.