What's this?!

This is a very little package with React hooks wrapping time-related vanilla Javascript functions, so you can use them with minimal effort in your React apps without having to worry about manual clean up, or writing boilerplate to pause/resume intervals etc.

Feature Overview

• Hooks for all timing-related vanilla JS functions like:
  • setInterval() –> useInterval() | MDN
  • setTimeout() –> useTimeout() | MDN
  • requestAnimationFrame() –> useAnimationFrame() | MDN
  • requestIdleCallback() –> useIdleCallback() | MDN
• …and additional utility hooks for common tasks like
  • throttling: useThrottledState(), useThrottle(), useDebounce()
  • GFX/animation/rendering: useAnimationFrameLoop()
  • reactive counters: useCounter(), useCountdown(), useTimer()
  • time: useClock()
  • async effects: useTimeoutEffect(), useIdleCallbackEffect()
  • oscillation: useOscillator()
• Reactive intervals: intervals can be controlled via pause, resume, start or stop
• A versatile API: customizable settings, many hook "flavors" depending on the use-case.
• Automatic clean-ups of pending timers, intervals etc. on unmount
• Callbacks are automatically memoized
• Full Typescript support
• Very lightweight (no transitive dependencies!)
• Tree-shakable — You only bundle what you use!

Installation

# via npm
npm i react-timing-hooks

# via yarn
yarn add react-timing-hooks

Documentation

https://ericlambrecht.github.io/react-timing-hooks/

How to migrate

https://ericlambrecht.github.io/react-timing-hooks/migrations/

Some Examples

A "status logger" with useInterval()

import { useInterval } from 'react-timing-hooks'

const StatusLogger = () => {
  const logUpdates = () => console.log('status update')
  // could also be intialized with { startOnMount: true } to immediately start the interval
  const { start, pause, resume, isPaused } = useInterval(logUpdates, 1000)

  return <div>
    <button onClick={start}>Do stuff</button>
    <button onClick={isPaused ? resume : pause}>Toggle Status Updates</button>
  </div>
}

Throttle a button click with useThrottle()

import { useThrottle } from 'react-timing-hooks'

const HelloWorld = () => {
  const [result, setResult] = useState(null)
  const updateResult = () => setResult(extremeMegaCalculation())
  
  const onButtonClick = useThrottle(updateResult, 1000)

  return <div>
    <button onClick={onButtonClick}>Spam me!</button>
    <p>Result: {result}</p>
  </div>
}

Display the user's browsing time using useTimer()

import { useTimer } from 'react-timing-hooks'

const BrowsingTime = () => {
  const [elapsedSeconds] = useTimer(0, { startOnMount: true })
  return <span>
    You've been browsing this page for {elapsedSeconds} seconds.
  </span>
}

Display the current time with useClock()

import { useTimeout } from 'react-timing-hooks'

const Clock = () => {
  // This will show a time like 1:13:56 PM (supports localized formats as well).
  // The displayed time will update every second
  const [currentTime] = useClock()
  return <span>{currentTime}</span>
}

A canvas renderer using useAnimationFrameLoop()

import { useAnimationFrameLoop } from 'react-timing-hooks'

const Renderer = () => {
  const delta = useRef(0)
  const canvasRef = useRef(null)
  const canvas = canvasRef.current
  const context = canvas.getContext('2d')

  const updateCanvas = (d) => {
    context.fillStyle = '#000000'
    context.fillRect(d, d, context.canvas.width, context.canvas.height)
  }

  const { start, stop, isStopped } = useAnimationFrameLoop(() => {
    delta.current += 1
    updateCanvas(delta.current)
  })
  
  return <>
    <canvas ref={canvasRef} {...props}/>
    <button onClick={isStopped ? start : stop}>
      {isStopped ? "Start rendering" : "Stop rendering"}
    </button>
  </>
}

Why does this exist?

I was once working for a company where the project required lots of timeouts and such. I quickly noticed that writing a timeout or anything similar requires a lot of boilerplate (if you don't do it quick and dirty). Dan Abramov showcased this in one of his blogposts a while a go.

This library is supposed to give you easy access to those time-related functionalities while keeping your code clean and concise. You will not have to manually clean up timers or intervals.

Another common use-case is pausing/resuming or starting/stopping intervals (or loops). This lib offers callbacks for that. So pausing is really just a matter of calling a pause() function for example.

Many frequent use cases also have their own utility hook, like useThrottle, useCountdown or useAnimationFrameLoop to make things even easier.

Needless to say, every hook is already tested and typed (so you don't have to).

Some "Before-/After-Code"

A simple interval that increments a counter on every second and can be manually started upon user input:

Before

import { useEffect, useState } from 'react'

const Counter = () => {
  const [counter, setCounter] = useState(0)
  const [startInterval, setStartInterval] = useState(false)
  const intervalId = useRef(null)

  useEffect(() => {
    if (startInterval) {
      intervalId.current = setInterval(() => setCounter(c => c + 1), 1000)
    }
  }, [startInterval])

  useEffect(() => {
    return function onUnmount() {
      if (intervalId.current !== null) {
        clearInterval(intervalId.current)
      }
    }
  }, [intervalId])

  return <>
    <button onClick={() => setStartInterval(true)}>Start counting</button>
    <p>{counter}</p>
  </>   
}

After

import { useState } from 'react'
import { useInterval } from 'react-timing-hooks'

const Counter = () => {
  const [counter, setCounter] = useState(0)
  
  const { start } = useInterval(() => setCounter(c => c + 1), 1000)

  return <>
    <button onClick={start}>Start counting</button>
    <p>{counter}</p>
  </>
}

Well,… actually, there is even a shorter way using the utility hook useTimer() 🙈

After After

import { useCounter } from 'react-timing-hooks'

const Counter = () => {
  const [counter, { start }] = useTimer(0)

  return <>
    <button onClick={start}>Start counting</button>
    <p>{counter}</p>
  </>
}

Another example: You might have a timeout that runs under a certain condition. In this case a cleanup has to be done in a separate useEffect call that cleans everything up (but only on unmount).

Before

import { useEffect } from 'react'

const TimeoutRenderer = ({ depA, depB }) => {
  const [output, setOutput] = useState(null)
  const timeoutId = useRef(null)

  useEffect(() => {
    if (depA && depB) {
      timeoutId.current = setTimeout(() => setOutput('Hello World'), 1000)
    }
  }, [depA, depB])

  useEffect(() => {
    return function onUnmount() {
      if (timeoutId.current !== null) {
        clearTimeout(timeoutId.current)
      }
    }
  }, [timeoutId])

  return output ? (
    <div>{output}</div>
  ) : null
}

After

import { useState } from 'react'
import { useTimeoutEffect } from 'react-timing-hooks'

const TimeoutRenderer = ({ depA, depB }) => {
  const [output, setOutput] = useState(null)

  useTimeoutEffect((timeout, clearAll) => {
    if (depA && depB) {
      timeout(() => setOutput('Hello World'), 1000)
    }
    // you could even add more timeouts in this effect 
    // without any more boilerplate
  }, [depA, depB])

  return output ? (
    <div>{output}</div>
  ) : null
}

In this case react-timing-hooks automatically took care of cleaning up the timeout for you (if the component is mounted for less than a second for instance).

Memoization

You don't have to worry about memoization of your callbacks (by using useCallback) for example. React Timing Hooks is taking care of that for you. So even if you pass a simple inline arrow function to one of these hooks, the return value (if there is one) will not change on every render but instead stay the same (i.e. it will be memoized).

This means something like this is safe to do:

const [foo, setFoo] = useState(null)
const onFooChange = useTimeout(() => console.log('foo changed one second ago!'), 1000)

// the following effect will run only when "foo" changes, just as expected.
// "onFooChange" is memoized and safe to use in a dependency array.
useEffect(() => {
  onFooChange()
}, [foo, onFooChange])

Bundle Size

The whole lib is tree-shakable, i.e. only hooks you actually use end up in your bundle. So far, we also do not use any transitive dependencies. So don't worry about the bundle size.

But check for yourself: https://bundlephobia.com/result?p=react-timing-hooks

Contributing

see CONTRIBUTING.md