links: [[]] --- # What is useCallBack in React? The `useCallBack` hook helps us to memoize the functions so that it prevents the re-creating of functions on every re-render. The *function* passed to the `useCallBack` hook is only recreated when one of it's dependencies are changed. # When to use useCallBack? Consider this scenario where you have to pass a callback function to the child. In functional components if you pass a callback function to child, whenever parent gets re-rendered, child also gets re-rendered, even when props doesn't change. To avoid this scenario, the useCallBack hook gives you a referential function that is same on multiple renders ## Referential Equality When you pass function as prop to child component, # When not to use useCallBack? **Performance optimizations are not free. They ALWAYS come with a cost but do NOT always come with a benefit to offset that cost.** --- tags: #basics , #react , #hooks sources: - [When to useMemo and useCallback](https://kentcdodds.com/blog/usememo-and-usecallback)