useMemo using useRef

useMemo.js

function useMemo(f, deps) {
  const state = React.useRef();
  if (state.current != null) {
    const [prevDeps, prevResult] = state.current;
    if (areArraysShallowEqual(deps, prevDeps)) {
      return prevResult;
    }
  }
  const result = f();
  state.current = [deps, result];
  return result;
}