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;
};

Function signature

  const useElapsedTime = (
    isPlaying: boolean,
    config?: {
      durationMilliseconds: number,
      onComplete?: () => void,
      isRepeated?: boolean
    }
  ): 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. If isRepeated is set, the elapsed time loop will start over once the duration is reached. 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>;
};

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>;
};

None-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, isRepeated: true };

const BounceAnimation = () => {
    const elapsedTime = useElapsedTime(isPlaying, config);
    const currentPoint = easing(elapsedTime, 0, pointsLength, durationMilliseconds) | 0;
    const colorValue = easing(elapsedTime, 0, 255, durationMilliseconds) | 0;
  
    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>
    );
};