It doesn't matter here, but it's worth mentioning, that when passing set state function, we can always use SetState<T> type defined in hook-types.js:

export type SetState<T> = ((T => T) | T) => void;

I don't think we need useMemo here. Here is Ashoat's answer for similar case in one of my diffs (https://phabricator.ashoat.com/D3377?id=10819#inline-21183)

There are two reasons to put something inside a React.useMemo:

1. The more important one, which is to make sure objects are not re-generated. In this case we have a primitive (boolean) so it does not matter, but if this useMemo returned an object or an array, then preventing it from regenerating one when the inputs do not change could reduce unnecessary render cycles deeper in the render tree
2. Sometimes there is some expensive calculation, and React.useMemo can save the processing time by caching the answer. In this case the calculation is extremely cheap

Ah thanks for pointing that out

Good point, thanks for catching that!