React Memo vs UseCallback: Which Should I Use?

What is the difference between React's memo and useCallback?

React's memo is a higher-order component that prevents unnecessary re-renders by memoizing the result of a component. useCallback, on the other hand, is a hook that returns a memoized version of a callback function, which helps to optimize performance by preventing the creation of new function instances on every render.

When should I use memo instead of useCallback?

You should use memo when you want to prevent a component from re-rendering unless its props change. Use useCallback when you want to optimize a function that is passed as a prop to a child component, ensuring that the function reference remains the same unless its dependencies change.

Can you give an example of when to use each?

Sure! Use memo for a component that renders a list of items where the list doesn't change often. Use useCallback for a function that handles a button click in a child component, ensuring that the function reference doesn't change unless its dependencies do.

Are there any performance drawbacks to using them?

Yes, both memo and useCallback can introduce overhead. If used excessively or inappropriately, they can lead to performance issues rather than improvements. It's important to profile your components to see if they actually benefit from these optimizations.