Hooks

usePrevious.js

function usePrevious(value) {
  const ref = useRef()
  useEffect(() => {
    ref.current = value
  }, [value])
  return ref.current
}

useRepetableArray.js

const useRepetableArray = (array, initial) => {
  const [state, setState] = useState(initial)

  const next = useCallback(
    (function () {
      let index = array.findIndex((val) => val === initial)
      return () => {
        if (++index >= array.length) index = 0
        setState(array[index])
      }
    })(),
    []
  )

  return [state, next]
}

useUpdated.js

const useUpdated = (cb, dependencies) => {
  const isMounted = useRef(false)
  useEffect(() => {
    isMounted.current && cb()
  }, dependencies)
  useEffect(() => {
    isMounted.current = true
  }, [])
}