UseMemo vs useCallback

Usememo vs usecallback: What is the difference?

UseMemo vs useCallback is an often asked question among programmers. But it’s not easy to call the difference when it comes to useCallback vs useMemo, so let’s find out in practice.

However, how can I define if React useMemo vs useCallback works better than otherwise? In the article, we will see the difference between useMemo and useCallback.

What are React usecallback vs usememo?

UseCallback and useMemo are the two primary ways of using memoization in JavaScript. Both are used to improve performance by caching the results of previously-performed computations. They both expect a function, but where they differ is that useCallback returns its function and reruns the function with different dependencies while useMemo calls its function and returns the result.

Use cases

UseCallback and useMemo are two of the most critical hooks in the React ecosystem. They are used to optimize rendering behavior and memoize expensive functions, respectively. Because of the asynchronous nature of hooks, both rely on a callback function that is provided with a list of dependencies. As both support lazy evaluation, developers can choose between them whenever their application requires memoization or optimization.

There is one big difference between useCallback and useMemo. When using useMemo, React will call it using its own code. It is a function that allows components to communicate with each other. Simultaneously, useCallback allows the user to call it.

Processing lots of data

If your job requires you to process a lot of data, Hooks can help. Use useMemo to do the work once at the first render and then return only a cached version on every other render. It’s perfect for data processing jobs that are done more than once per run.

UseMemo vs useCallback – which is better

UseMemo often gets confused with useCallback. They are both similar but not equal. UseCallback allows you to set a function as the contents of a variable, but it does not automatically execute it. UseMemo, on the other hand, makes your function more dynamic by making it a string that evaluates evaluation in your browser when needed. The two approaches have virtually the same result, but they achieve it in different ways.

Suppose you can pass a function to useCallback or useMemo both, and you can use that function with empty dependencies. In that case, you could define the process outside of the component (and do without useCallback or useMemo).

useCallback allows you to pass in a function that will be called by the parent function when it is ready to be used. This is definitely helpful if you are creating a child component from a parent component, which may not be ready until later. useMemo allows you to pass in a function that will be called and returned directly from the parent component without having to return a new element for it.

UseMemo is NOT a good option for other hooks

On the other hand, React can keep track of changes, and it can always repaint the affected areas if need be. This is why React has a reputation for efficiently managing state changes. Remember, useCallback does not receive props as part of its arguments like React does.

UseMemo is more flexible than useCallback, as it does not require a custom event interface to be passed to it. It is able to function on any object that matches the format.

The useMemo hook has the option of being undefined, but doing so is a gamble. Leaving the dependencies undefined means that there is no memory cache, and re-renders may be needed. In TypeScript definitions, it is possible to use this code for useMemo, but it has bugs and shouldn’t be used for optional dependencies because mistakes could cause errors.


UseMemo vs useCallback is a very interesting dilemma. React hooks have replaced several methods and classes, but developers should still be aware of their use. Even though useMemo doesn’t particularly improve performance, it’s still important to know how React can replace it with useCallback in some instances. Hopefully, we will see some changes soon, which will utilize just one hook for all needs.

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