use-anim

Super small easy-to-use hook-based animation library for React.

• Zero dependencies
• Written in TypeScript
• Very small code-base

Check it out on CodeSandbox!

Installation

npm install use-anim

or

yarn add use-anim

Usage

import React, {useState} from 'react'
import { useAnim, easing } from 'use-anim'

// A component that makes its children
// appear with a fancy fade animation
const FadeReveal = ({ children }) => {
  const [opacity, setOpacity] = useState(0)
  const [translation, setTranslation] = useState(-30)

  useAnim({
    duration: 500,
    easing: easing.easeOutQuad,
  }, t => {
    setOpacity(t)
    setTranslation(-30*(1-t))
  })

  return (
    <div style={{ opacity, transform: `translateY(${translation}px)`}}>
      {children}
    </div>
  )
}

AnimationConfig

To start an animation you give useAnim an object compatible with the following interface as the first parameter:

interface AnimationConfig {
  duration: number,
  easing?: Easing,
  started?: boolean,
  playMode?: PlayMode,
}

duration: How long does the animation run in milliseconds.

easing: A function that accepts a value t in range 0-1 and returns a modified number in the same range. This is used to get a more smooth animation.

started: If the animation should not start automatically, you can set this value to false. The animation will start when this is changed to true.

playMode: Controls playback of the animation. Valid values are: forward (default), reverse, loop and pingPong.

The second parameter, known as updateFunc, is a function which takes a parameter t. This is called every frame during the animation, with t running from 0 to 1.

Drawbacks 😕

As pointed out by a good Reddit user, using setState every frame can be expensive. It will trigger a rerender of the component and all its children. Therefore I recommend using this library for simple components that reside near the leafs.

Contributing 👍

Pull requests are very welcome

To test locally, you can use:

npm run build
npm run copy-to-example

Note: The copy-to-example script uses the cp command which is not available through CMD on Windows. You can use Git Bash instead.

This will compile TypeScript to JavaScript in a folder called lib and copy this folder to example/node_modules/use-anim. You can now test your new addition in the example project.

cd example
npm start

Note: Remember to run npm install in both the root directory and the example directory.