Selectors

Calling the hook bare re-renders on any state change:

const everything = useCounter();

Pass a selector to subscribe to just a slice — the component re-renders only when that slice changes:

const count = useCounter((s) => s.count);

Custom equality

Selectors that return a new object every render would always re-render. Pass an equality function — shallow is exported for the common case:

import { shallow } from "unistash";

const { a, b } = useCounter(
  (s) => ({ a: s.count, b: s.doubled }),
  shallow,
);

The default equality is Object.is.