src/use-interval.js


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

// lifted from here:
// https://overreacted.io/making-setinterval-declarative-with-react-hooks/
import React, { useState, useEffect, useRef } from 'react'

export const useInterval = (callback, delay) => {
  const savedCallback = useRef()

  // Remember the latest callback.
  useEffect(
    () => {
      savedCallback.current = callback
    },
    [callback]
  )

  // Set up the interval.
  useEffect(
    () => {
      function tick() {
        savedCallback.current()
      }
      if (delay !== null) {
        let id = setInterval(tick, delay)
        return () => clearInterval(id)
      }
    },
    [delay]
  )
}