velocity-react

React components for interacting with the Velocity DOM animation library.

Read our announcement blog post for details about why and how we built this.

See the live demo.

Latest version: v1.4.2 Avoids react-dom warnings in test for Transition props.

Note: v1.1.0 and later require React 0.14.x Note: v1.3.0 and later require React 15.3.x and should work with React 16

Running the demo

$ git clone https://github.com/twitter-fabric/velocity-react.git
$ cd velocity-react
$ npm install
$ npm run demo

Visit http://localhost:8080/webpack-dev-server/ in your browser. Hot reloading is enabled, if you want to tweak the code in main.jsx.

Installation

The velocity-react library is provided as an NPM package:

$ npm install --save velocity-react

The VelocityComponent and VelocityTransitionGroup components, as well as the velocityHelpers utilities, are distributed as ES5-compatible JavaScript files with CommonJS require statements. You will need a dependency tool such as Browserify, RequireJS, or webpack to use them on the web.

This package depends directly on Velocity, as well as lodash for a handful of utility functions (which are required individually to try and keep bundle size down).

To use the Velocity UI Pack, which includes a library of transitions and support for the stagger, drag, and backwards options, require it along with Velocity at an entry point to your app:

  require('velocity-animate');
  require('velocity-animate/velocity.ui');

Note: Depending upon where your version of NPM places dependencies, you may need to explicitly require velocity-animate in your package.json to be able to require velocity-animate/velocity.ui.

It is assumed that your application already depends on react and react-dom at v15. If you're still at React 0.13, use v1.0.1 of this package. Other than dependencies, it is the same as v1.1.0.

Usage

VelocityComponent

Component to add Velocity animations to a child node or one or more of its descendants. Wraps a single child without adding additional DOM nodes.

Example

  <VelocityComponent animation={{ opacity: this.state.showSubComponent ? 1 : 0 }} duration={500}>
    <MySubComponent/>
  </VelocityComponent>

Details

The API attempts to be as declarative as possible. A single animation property declares what animation the child should have. If that property changes, this component applies the new animation to the child on the next tick.

By default, the animation is not run when the component is mounted. Instead, Velocity's finish command is used to jump to the animation's end state. For a component that animates out of and back in to a default state, this allows the parent to specify the "animate into" animation as the default, and therefore not have to distinguish between the initial state and the state to return to after animating away.

Properties

animation: Either an animation key or hash defining the animation. See Velocity's documentation for what this can be. (It is passed to Velocity exactly.)

runOnMount: If true, runs the animation even when the component is first mounted.

targetQuerySelector: By default, this component's single child is animated. If targetQuerySelector is provided, it is used to select descendants to apply the animation to. Use with caution, only when you're confident that React's reconciliation will preserve these nodes during animation. Also note querySelectorAll's silly behavior w.r.t. pruning results when being called on a node. A special value of "children" will use the direct children of the node, since there isn't a great way to specify that to querySelectorAll.

interruptBehavior: Specifies what should happen to an in-progress animation if the animation property changes. By default is stop, which stops it at its current position, letting the new animation use that as a starting point. This generally gives the smoothest results. Other options are finish, which jumps the animation to its end state, and queue, which will proceed with the new animation only after the old one has finished. These options may be necessary to avoid bad behavior when certain built-in effects like "slideUp" and "slideDown" are toggled rapidly.

Unrecognized properties are passed as options to Velocity (e.g. duration, delay, loop).

Methods

runAnimation: Triggers the animation immediately. Useful for when you want an animation that corresponds to an event but not a particular model state change (e.g. a "bump" when a click occurs).

VelocityTransitionGroup

Component to add Velocity animations around React transitions. Delegates to the React TransitionGroup addon.

Example

  <VelocityTransitionGroup enter={{animation: "slideDown"}} leave={{animation: "slideUp"}}>
    {this.state.renderSubComponent ? <MySubComponent/> : undefined}
  </VelocityTransitionGroup>

Properties

enter: Animation to run on a child component being added

leave: Animation to run on a child component leaving

runOnMount: if true, runs the enter animation on the elements that exist as children when this component is mounted.

Any additional properties (e.g. className, component) will be passed to the internal TransitionGroup.

enter and leave should either be a string naming an animation registered with UI Pack, or a hash with an animation key that can either be a string itself, or a hash of style attributes to animate (this value is passed to Velocity its the first arg).

Note: To make it easier to write consistent “enter” animations, the “leave” animation is applied to elements before the “enter” animation is run. So, for something like opacity, you can set it at 0 in “leave” and 1 in “enter,” rather than having to specify that “enter” should start at 0.

If enter or leave is a hash, it can additionally have a style value that is applied the tick before the Velocity animation starts. Use this for non-animating properties (like position) that are prerequisites for correct animation. The style value is applied using Velocity's JS -> CSS routines, which may differ from React's.

Any hash entries beyond animation and style are passed in an options hash to Velocity. Use this for options like stagger, reverse, &c.

Statics

disabledForTest: Set this to true globally to turn off all custom animation logic. Instead, this component will behave like a vanilla TransitionGroup.

velocityHelpers

registerEffect

Takes a Velocity "UI pack effect" definition and registers it with a unique key, returning that key (to later pass as a value for the animation property). Takes an optional suffix, which can be "In" or "Out" to modify UI Pack's behavior.

Unlike what you get from passing a style hash to VelocityComponent's animation property, Velocity "UI pack effects" can have chained animation calls and specify a defaultDuration, and also can take advantage of stagger and reverse properties on the VelocityComponent.

You will need to manually register the UI Pack with the global Velocity in your application with:

  require('velocity-animate');
  require('velocity-animate/velocity.ui');

If, even with the above statements, you see errors like Velocity: First argument (transition.shrinkIn) was not a property map, a known action, or a registered redirect. Aborting. it is likely that there are 2 copies of velocity-animate in your node_modules. Use npm dedupe to collapse them down to one.

It might also be necessary to require the velocity-animate package explicitly in your package.json.

See: http://velocityjs.org/#uiPack

Server-side rendering

The VelocityComponent and VelocityTransitionGroup components are (as of v1.0.1) tolerant of being rendered on the server: they will no-op and render their children naturally. If your initial animation end states match natural rendering this will be exactly what you want. Otherwise, you may notice a flash when the JS is applied and the initial animations are resolved.

Bugs

Please report any bugs to: https://github.com/twitter-fabric/velocity-react/issues

We welcome contributions! Note that when testing local changes against local projects you’ll need to avoid npm link since it typically will cause duplicate instances of React in the client. (You’ll often see this manifest as firstChild undefined errors.)

Acknowledgments

Thanks to Julian Shapiro and Ken Wheeler for creating and maintaining Velocity, respectively, and for working with us to release this library.

Thanks to Kevin Robinson and Sam Phillips for all of the discussions and code reviews.

License

Copyright 2017 Google Inc.

Licensed under the MIT License: https://opensource.org/licenses/MIT