my-react-hooks

A collection of my React Hooks for me.

Provides type definitions for TypeScript.

npm i my-react-hooks

API

useRefMemo

Like useMemo, but always returns the same ref object whose content is updated with the return value of given function every time one of dependent values is updated.

function Test() {
  const [state, setState] = useState(0);
  const stateRef = useRefMemo(() => state, [state]);
  useEffect(() => {
    // `console.log` always outputs *current* value of `state`.
    return setInterval(() => console.log(stateRef.current), 1000);
  }, []);
  return /* omitted */;
}

useShallowMemo

Like useMemo, but returned value is not updated when a new value is shallow-equal to previous one.

function Test({ foo, bar }) {
  // the same object is returned when (foo, bar) is updated from (5, 0) to (10, 5).
  const diff = useShallowMemo(
    () => ({
      diff: foo - bar,
    }),
    [foo, bar],
  );
  return /* omitted */;
}

useUpdateSignal

Given a function which compares previous and current dependencies, returns a new integer every time that function returns true. Use when you need sophisticated control over when useEffect and likewise are fired.

function Test({ obj }) {
  // updated when `obj` changed and the `foo` property of new `obj` is 'foo'.
  const signal = useUpdateSignal(([prevObj], [obj]) => obj.foo === "foo", [
    obj,
  ]);
  // useEffect called is called whenever above condition is satisfied.
  useEffect(() => {
    cosnole.log(obj);
  }, [signal]);
  return /* omitted */;
}

Note for TypeScript users: Dependencies should have const assertions (as [ obj ] as const) so that the type of callback is properly inferred.

License

MIT

Contribution

Welcome

TODO

• Write tests