useMemo

Difference between useMemo() and useCallback()

The other Hook that’s useful for performance optimization is the useMemo() Hook. We call it in the following way:

const memoizedValue = useMemo(valueGetterFunction, dependencyArray);

It works similarly to the useCallback() Hook. However, it does not provide a unique identity for the function going in, but for the return value from the function, which has been passed into the useMemo() Hook.

So, the following snippet of code:

useCallback(fn, deps);

corresponds to this snippet:

useMemo(() => fn, deps);

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