JSPM – react-spring@1.2.1

Package Exports

react-spring

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (react-spring) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

npm install react-spring

Demo: https://codesandbox.io/embed/oln44nx8xq

React-spring is a wrapper around a cooked down fork of Facebooks animated. It is trying to bridge react-motion and animated in fact. React-motion is great but doesn't interpolate well, shifting from one state to another is hard as it can't deal with colors, gradients, paths, etc. Animated does that well, but the downside is manually having to manage animation-handles, doing stopping/cleaning chores.

This lib has a similar api as react-motion (Spring -> Motion, from -> defaultStyles, to -> styles) while you can feed it everything animated can take in.

import { Spring } from 'react-spring'

const TRIANGLE = 'M20,380 L380,380 L380,380 L200,20 L20,380 Z'
const RECTANGLE = 'M20,20 L20,380 L380,380 L380,20 L20,20 Z'
const RED = '#c23369'
const GREEN = '#28d79f'

const Content = ({ toggle, color, opacity, scale, path, start, stop, end }) => (
    <div style={{ background: `linear-gradient(to bottom, ${start} ${stop}, ${end} 100%)` }}>
        <svg
            onClick={toggle}
            style={{ opacity, transform: `scale3d(${scale}, ${scale}, ${scale})` }}
            version="1.1"
            viewBox="0 0 400 400">
            <g fill={color} fillRule="evenodd">
                <path id="path-1" d={path} />
            </g>
        </svg>
    </div>
)

class App extends React.Component {
    state = { toggle: true }
    toggle = () => this.setState(state => ({ toggle: !state.toggle }))
    render() {
        const toggle = this.state.toggle
        return (
            <Spring
                // Default values, optional ...
                from={{ opacity: 0 }}
                // Will animate to ...
                to={{
                    // Can be numbers, colors, paths, degrees, percentages, ...
                    opacity: 1,
                    color: toggle ? RED : GREEN,
                    start: toggle ? RED : 'black',
                    end: toggle ? 'black' : GREEN,
                    stop: toggle ? '0%' : '50%',
                    scale: toggle ? 1 : 2,
                    path: toggle ? TRIANGLE : RECTANGLE,
                }}
                // You can finetune spring settings
                config={{ friction: 1, tension: 10 }}
                // All additional props will be spread over the child
                toggle={this.toggle}
                // Child as function/render-prop, receives interpolated values
                children={Content}
            />
        )
    }
}

Native rendering

Demo: https://codesandbox.io/s/882njxpz29

React-spring will re-render the receiving component on every frame. It is usually fine and gives you more freedom to animate whatever you like. If you need more performance supply the native flag. Now your component will only render once and all updates will efficiently be applied to it outside of Reacts render loop.

This has a few gotchas:

You can only animate styles!
The components that receive your styles have to be special, animated components. The styles are opaque objects, not regular styles!
If you use transforms, make sure it's an array

import { Spring, animated } from 'react-spring'

const DIV = animated.div
const SVG = animated.createAnimatedComponent('svg')

const Content = ({ toggle, color, backgroundColor, transform }) => (
    <DIV style={{ backgroundColor }}>
        <SVG style={{ transform }} version="1.1" viewBox="0 0 400 400">
            <g style={{ color }} fillRule="evenodd" onClick={toggle}>
                <path id="path-1" d="M20,380 L380,380 L380,380 L200,20 L20,380 Z" />
            </g>
        </SVG>
    </DIV>
)

class App extends React.Component {
    state = { toggle: true }
    toggle = () => this.setState(state => ({ toggle: !state.toggle }))
    render() {
        const toggle = this.state.toggle
        return (
            <Spring
                native
                from={{ color: 'black' }}
                to={{
                    color: toggle ? '#247BA0' : '#70C1B3',
                    backgroundColor: toggle ? '#B2DBBF' : '#F3FFBD',
                    transform: [{ rotate: toggle ? '0deg' : '180deg' }, { scale: toggle ? 0.6 : 1.5 }],
                }}
                toggle={this.toggle}
                children={Content}
            />
        )
    }
}

By default you can use animated.div, animated.span and animated.img, you can create your own by calling: animated.createAnimatedComponent('h1') or whatever element you need.