use-elapsed-time

useElapsedTime React hook

The only hook you need to perform JavaScript animations in React.

• Lightweight: only 2KB
• Built with 0 dependencies
• Toggle play/pause
• Combine with any easing function to get the right animation

Installation

yarn add use-elapsed-time

or

npm install use-elapsed-time

Basic usage

import { useElapsedTime } from 'use-elapsed-time';

const MyComponent = () => {
  const isPlaying = true;
  const elapsedTime = useElapsedTime(isPlaying);
  
  return elapsedTime;
};

Basic usage demo

Function signature

  function useElapsedTime(
    isPlaying: boolean,
    config?: {
      durationMilliseconds: number,
      onComplete?: () => undefined | [shouldRepeat: boolean, delay: number]
    }
  ): number;

The first argument isPlaying indicates if the loop to get the elapsed time is running or it is paused. The second argument config is optional and it makes sense when the animation duration durationMilliseconds is defined. onComplete callback will be fired when the duration is reached. onComplete can be used to restart the elapsed time loop by returning an array where the first element shouldRepeat indicates if the loop should start over and second element delay specifies the delay before looping again in milliseconds.

The hook returns elapsed time in milliseconds.

Use cases

Countdown timer

import { useElapsedTime } from 'use-elapsed-time';

const isPlaying = true;
const durationMilliseconds = 5000;
const config = { durationMilliseconds };

const CountDownTimerComponent = () => {  
  const elapsedTime = useElapsedTime(isPlaying, config);
  const remainingTime = Math.ceil((durationMilliseconds - elapsedTime) / 1000);
  
  return <div>Remaining {remainingTime} seconds</div>;
};

Countdown timer demo

Count Up

import { useElapsedTime } from 'use-elapsed-time';

const easing = (t, b, c, d) => {
    return c*((t=t/d-1)*t*t + 1) + b;
};

const isPlaying = true;
const start = 90;
const end = 300;
const durationMilliseconds = 3000;
const config = { durationMilliseconds };

const CountUpComponent = () => {
    const elapsedTime = useElapsedTime(isPlaying, config);
    const currentValue = easing(elapsedTime, start, end - start, durationMilliseconds);

    return <div>{Math.round(currentValue)}</div>;
};

Count up demo

Non-liner path animation

import { useElapsedTime } from 'use-elapsed-time';

const easing = (t, b, c, d) => {
    return c*((t=t/d-1)*t*t + 1) + b;
};

// define the path by an array of cordinates [x, y] 
const points = [[150,200],[151,201], ...];
const pointsLength = 530 - 1;
const isPlaying = true;
const durationMilliseconds = 4000;
const config = { durationMilliseconds, onComplete: () => [true] };

const BounceAnimation = () => {
    const elapsedTime = useElapsedTime(isPlaying, config);
    const currentPoint = easing(elapsedTime, 0, pointsLength, durationMilliseconds);
    const colorValue = easing(elapsedTime, 0, 255, durationMilliseconds);
  
    const pointStyle = {
        position: 'absolute',
        left: points[currentPoint][0],
        top: points[currentPoint][1],
        width: 20,
        height: 20,
        transform: 'translate(-50%, -50%)',
        borderRadius: '50%',
        background: `rgba(${colorValue}, 0, ${255 - colorValue})`
    };

    return (
        <div style={{ position: 'relative', width: 800, height: 600 }}>
            <div style={pointStyle} />
        </div>
    );
};

Demo non-linear animation