React-Touch

React-Touch is a set of wrapper components that handle touch interactions in a more declarative way, abstracting out and giving you hooks into behaviors such as dragging, holding, swiping, and custom gestures. React-Touch also works with mouse events as well.

Here's a quick example of the API.

import { Holdable } from 'react-touch';
<Holdable onHoldComplete={handleHold}>
  ({ holdProgress }) => <Button style={{opacity: holdProgress}} />
</Holdable>

Try it out

npm install react-touch --save

Demos

• Emulating a Smartphone Dashboard

What Does This Library Do?

If you've ever written mobile web software, then you might've found yourself needing the ability to touch drag a component, measure a hold, or react to a swipe or gesture. This library is a set of wrapper components that abstract out the details of those things so you can wrap your components and move on.

API

Exports:

• defineHold
• defineSwipe
• Holdable
• Draggable
• Swipeable
• CustomGesture

Helpers

defineHold(config?: Object)

Used in conjuction with Holdable, defineHold is an optional helper function that creates a configuration for your holdable component. The arguments to it are:

• config: Optional. Object with the following keys:
  • updateEvery: Optional. Defaults to 250. Units are in milliseconds.
  • holdFor: Optional. Defaults to 1000. Units are in milliseconds.

Example Usage

const hold = defineHold({updateEvery: 50, holdFor: 500});
<Holdable config={hold} onHoldComplete={handleHold}>
  <Button />
</Holdable>

defineSwipe(config?: Object)

Used in conjuction with Swipeable, defineSwipe is an optional helper function that creates a configuration for your swipeable component. The arguments to it are:

• config: Optional. Object with the following keys:
  • swipeDistance: Optional. Defaults to 100. Units are in pixels.

Example Usage

const swipe = defineSwipe({swipeDistance: 50});
<Swipeable config={swipe} onSwipeLeft={deleteEmail}>
  <Email />
</Swipeable>

Components

<Holdable />

Used to create a component that understands holds. Holdable will give you hooks for the progress and the completion of a hold. You can pass a component or a function as its child. Passing a function will gain you access to the hold progress.

Example Usage:

<Holdable onHoldComplete={handleHold}>
  ({ holdProgress }) => <Button style={{opacity: holdProgress}} />
</Holdable>

Props

• onHoldProgress?: Function When the hold makes progress, this callback is fired. Update intervals can be adjusted by the updateEvery key in the configuration.

• onHoldComplete?: Function When the hold has completed, this callback is fired. Length of hold can be adjusted by the holdFor key in the configuration.

Callback Argument Keys

• holdProgress

<Draggable />

Used to create a component that can be dragged. Draggable requires a style prop defining its initial position and will pass updates to the child component via a callback.

Example Usage

<Draggable style={{translateX: 150, translateY: 200}}>
  {({translateX, translateY}) => {
    return (
      <div style={{transform: `translate3d(${translateX}px, ${translateY}px, 0)`}}>
        <Bubble />
      </div>
    );
  }}
</Draggable>

Props

• style: Object Required. An object that defines the initial position of the draggable component. You can pass any of the following styles to it and they'll be updated and passed back out in the callback with every animation tick.

  • translateX
  • translateY
  • top
  • left
  • right
  • bottom

Callback Argument Keys

Any of the above keys depending on what you set as your style. Additionally:

• dx
• dy

<Swipeable />

Used to create a component that understands swipes. Swipeable gives you hooks to the swipe directions up, down, left, right, with the swipe threshold being customized using the defineSwipe helper.

Example Usage:

<Swipeable onSwipeLeft={deleteEmail}>
  <Email />
</Swipeable>

Props

• onSwipeLeft?: Function When the swipe threshold has been passed in the left direction, fire this callback.

• onSwipeRight?: Function When the swipe threshold has been passed in the right direction, fire this callback.

• onSwipeDown?: Function When the swipe threshold has been passed in the down direction, fire this callback.

• onSwipeUp?: Function When the swipe threshold has been passed in the up direction, fire this callback.

<CustomGesture />

Used to create a component that understands a customized gesture. Gestures are passed through the config prop. When the gesture is recognized, onGesture will fire.

Gestures are just a combination of discrete linear movements. For instance, a "C" gesture would be composed of a left, down-left, down, down-right, and right. The user doesn't have to do this perfectly, the library will do a distance calculation and fire or not fire the onGesture callback based off that. This algorithm is a port of a Swift library by Didier Brun.

Example Usage:

import { CustomGesture, moves } from 'react-touch';

const CIRCLE = [
  moves.RIGHT,
  moves.DOWNRIGHT,
  moves.DOWN,
  moves.DOWNLEFT,
  moves.LEFT,
  moves.UPLEFT,
  moves.UP,
  moves.UPRIGHT,
  moves.RIGHT,
];

<CustomGesture config={CIRCLE} onGesture={unlockApp}>
  <AppLockScreen />
</CustomGesture>

Props

• onGesture?: Function Callback fired when the gesture is complete.

Advanced Usage

Want to be able to drag and hold a component? You can wrap react-touch components with other react-touch components to achieve this. For example:

const hold = defineHold({updateEvery: 50, holdFor: 500});
<Holdable config={hold} onHoldComplete={() => console.log('held out')}>
  <Draggable style={{translateX: 150, translateY: 200}}>
    {({translateX, translateY, holdProgress}) => {
      return (
        <div style={{transform: `translate3d(${translateX}px, ${translateY}px, 0)`}}>
          <Bubble style={{opacity: holdProgress}} />
        </div>
      );
    }}
  </Draggable>
</Holdable>

Notice the callback argument keys are the combination of the two parent components. This feature means you don't have to do multiple nested callbacks to achieve the same effect.