useMemo

It memoizes the calculation result, not the external values themselves
useMemo caches the value returned by its calculation function. Values defined outside the component, such as module constants or imports, are usually already stable; React may compare them if they are included as dependencies, but useMemo does not memoize those external values themselves.
It automatically memoizes all external values
It requires all external constants to be listed as dependencies
It throws an error when external values are referenced

Question 17 of 20 in useMemo