JSPM – react-spring@1.2.4

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 Chenglou's React-motion and animated as both have their pros and cons, but definitively could benefit from one another:

React-motion

Declarative api that doesn't involve manual management of handles
Performance suffers because components are re-rendered on every frame
Can't interpolate between raw state as it doesn't know colors, paths, gradients, etc.

Animated

Very powerful, lots of features
Very efficient, it does not re-render components and changes styles directly in the dom
Managing and orchestrating handles becomes a real chore

This lib inherits React-motions api (Spring -> Motion, from -> defaultStyles, to -> styles) while you can feed it everything animated can take in as well as allowing for native animations.

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/embed/882njxpz29

Like React-motion by default we'll render the receiving component on every frame as it gives you more freedom to animate whatever you like. If you need more performance then pass the native flag. Now your component will only render once and all updates will be applied straight in the dom.

Just be aware of the following conditions:

You can only animate native styles and props
If you use transforms make sure it's an array
Receiving components have to be "animated components"
The values you receive are opaque objects, not regular values

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

const Content = ({ toggle, fill, backgroundColor, transform, path }) => (
    <animated.div style={{ backgroundColor }}>
        <animated.svg style={{ transform, fill }} version="1.1" viewBox="0 0 400 400">
            <g fillRule="evenodd" onClick={toggle}>
                <animated.path id="path-1" d={path} />
            </g>
        </animated.svg>
    </animated.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={{ fill: 'black' }}
                to={{
                    fill: toggle ? '#247BA0' : '#70C1B3',
                    backgroundColor: toggle ? '#B2DBBF' : '#F3FFBD',
                    transform: [{ rotate: toggle ? '0deg' : '180deg' }, { scale: toggle ? 0.6 : 1.5 }],
                    path: toggle ? TRIANGLE : RECTANGLE,
                }}
                toggle={this.toggle}
                children={Content}
            />
        )
    }
}

If you need to interpolate native styles, use animated.template. For instance, given that you receive startColor and endColor as animatable values you could do it like so:

const Content = ({ startColor, EndColor }) => {
    const background = animated.template`linear-gradient(bottom ${startColor} 0%, ${EndColor} 100%)`
    return (
        <animated.div style={{ background }}>
            ...
        </animated.div>
    )
)