Purpose of useCallback

• Preventing Unnecessary Renders: In React, when a component re-renders, all functions defined within it are recreated. If a callback function is passed down to child components as a prop, and it’s recreated on every render of the parent component, it can lead to unnecessary re-renders of the child components, even if the callback function’s logic hasn’t changed.
• Optimizing Performance: By memoizing callback functions, useCallback can improve performance, especially in scenarios where callback functions are passed to child components or are dependencies of other hooks like useEffect. When a function is memoized with useCallback, React only recreates it if any of the dependencies specified in the dependency array have changed.

The useCallback hook in React is used to memoize functions, which means it returns a memoized version of the callback function that only changes if one of the dependencies has changed. Its primary purpose is to optimize performance by avoiding unnecessary re-renders in components that rely on callback functions as dependencies.

Syntax:

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