react-use-gesture

What is react-use-gesture?

react-use-gesture is a React hook library that allows you to handle gestures in your React applications. It provides a simple and declarative way to manage complex gesture interactions such as dragging, pinching, and scrolling.

What are react-use-gesture's main functionalities?

Drag

The `useDrag` hook allows you to handle drag gestures. In this example, the `bind` function is used to attach the drag event to a `div` element. The `offset` property provides the current position of the dragged element.

```jsx
import React from 'react';
import { useDrag } from 'react-use-gesture';

function Draggable() {
  const bind = useDrag(({ offset: [x, y] }) => {
    console.log(`Dragged to: ${x}, ${y}`);
  });

  return <div {...bind()} style={{ width: 100, height: 100, background: 'lightblue' }}>Drag me</div>;
}

export default Draggable;
```

Pinch

The `usePinch` hook allows you to handle pinch gestures. In this example, the `bind` function is used to attach the pinch event to a `div` element. The `offset` property provides the current distance and angle of the pinch gesture.

```jsx
import React from 'react';
import { usePinch } from 'react-use-gesture';

function Pinchable() {
  const bind = usePinch(({ offset: [d, a] }) => {
    console.log(`Pinched to: ${d}, ${a}`);
  });

  return <div {...bind()} style={{ width: 100, height: 100, background: 'lightgreen' }}>Pinch me</div>;
}

export default Pinchable;
```

Scroll

The `useScroll` hook allows you to handle scroll gestures. In this example, the `bind` function is used to attach the scroll event to a `div` element. The `offset` property provides the current scroll position.

```jsx
import React from 'react';
import { useScroll } from 'react-use-gesture';

function Scrollable() {
  const bind = useScroll(({ offset: [x, y] }) => {
    console.log(`Scrolled to: ${x}, ${y}`);
  });

  return <div {...bind()} style={{ width: 200, height: 200, overflow: 'scroll', background: 'lightcoral' }}>
    <div style={{ width: 400, height: 400 }}>Scroll me</div>
  </div>;
}

export default Scrollable;
```

Other packages similar to react-use-gesture

react-dnd

react-dnd is a set of React utilities to help you build complex drag-and-drop interfaces while keeping your components decoupled. It is more focused on drag-and-drop interactions and provides a higher level of abstraction compared to react-use-gesture.

react-spring

react-spring is a spring-physics-based animation library for React applications. While it is primarily an animation library, it can be used in conjunction with gesture libraries to create smooth and interactive animations. It complements react-use-gesture well but serves a different primary purpose.

react-interactions

react-interactions is a library for handling user interactions in React applications. It provides a set of hooks for managing various types of interactions, including gestures. It is similar to react-use-gesture but offers a broader range of interaction handling.

README

These demos are real, click them!

npm install react-use-gesture

Ever thought about doing that sidebar pull-out, a view pager, some slider, any gesture on the web basically, and dropped the idea because it's too hard? In that case, this is your lib.

React-use-gesture is a React hook that lets you bind richer mouse and touch events to any component or view. With the data you receive, it becomes trivial to set up gestures, and often takes no more than a few lines of code.

You can use it stand-alone, but to make the most of it you should combine it with an animation library like react-spring, though you can most certainly use any other.

Api

import useGesture from 'react-use-gesture'

// in your component
const bind = useGesture(actions, config)

The api is straight forward. You bind handlers to your view, specify the actions you want to respond to (drag, pinch, hover, move, scroll or wheel) and you will receive events when you interact with the component. These events include the source dom event, but also carry additional kinematics such as velocity, distance, delta, etc.

Hooks allow gestures to be re-used for more than one view (you can use the same bind() function multiple times!).

// Rough example that makes a div respond to drag and scroll gestures
function myComponent() {
  const bind = useGesture({
    onDrag: dragState => doStuffOnDrag,
    onScroll: scrollState => doStuffOnScroll
  }, { event : { passive: false } })
  return <div {...bind(optionalArgs)} />
}

React-use-gesture only adds listeners, nothing more!

Contrary to libraries such as react-pose that provide out of the box draggable components, binding a drag handler to a div through react-use-gesture doesn’t make it draggable. For that, you will need to pass it styling elements based on the values returned by useGesture.

Making things move

function myComponent() {
  const [[x, y], set] = React.useState([0, 0])
  const bind = useGesture({ onDrag: ({ local }) => set(local) })
  return <div {...bind()} style={{ transform: `translate3d(${x}px,${y}px,0)` }} />
}

When the user drags the div that receives the bind() prop, useGesture updates the state of the component and the div gets positioned accordingly.

In this case we fetch local off the gesture event, which keeps track of delta positions after release. Deltas are especially important in this lib, because they make it possible to use transitions for positioning, instead of doing complex getBoundingClientRect() calculations to figure out where a node went on the screen.

Avoid re-rendering (preferred)

In the example we’ve just seen, the component gets re-rendered every time useGesture drag handler fires, which can be taxing. To avoid re-rendering you may want to use libraries such as react-spring that allow to animate dom elements without setting state and therefore without triggering new renders.

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

function myComponent() {
  const [{ local }, set] = useSpring(() => ({ local: [0, 0] }))
  const bind = useGesture({ onDrag: ({ local }) => set({ local }) })

  return <animated.div {...bind()} style={{ transform: local.interpolate((x, y) => `translate3d(${x}px,${y}px,0)`) }} />
}

Because we’re now using animated.div, we’re able to make the element draggable without provoking new renders every time its position should update.

Supported gestures

In addition to drag, react-use-gesture also supports scroll gestures, and mouse-specific gestures such as move, wheel and hover (entering and leaving an element), and touch-specific pinch. Every gesture has a handler that you can pass to useGesture, and you can even pass multiple handlers for the element to respond to different gestures.

const bind = useGesture({
  onDrag: state => {...},     // fires on drag
  onPinch: state => {...},     // fires on pinch
  onScroll: state => {...},   // fires on scroll
  onHover: state => {...},    // fires on mouse enter, mouse leave
  onMove: state => {...},     // fires on mouse move over the element
  onWheel: state => {...}     // fires on mouse wheel over the eleement
})

on[Gesture]Start and on[Gesture]End

Drag, pinch, move, scroll and wheel gestures also have two additional handlers that let you perform actions when they start or end. For example, onScrollEnd fires when the user finished scrolling.

Note #1: on[Gesture]Start and on[Gesture]End methods are provided as a commodity. on[Gesture] handlers receive first and last properties that indicate if the event fired is the first (i.e. gesture has started) or the last one (i.e. gesture has ended).

Note #2: since browsers don't have native event listeners for when scroll, move or wheel ends, react-use-gesture debounces these events to estimate when they stopped. One of the consequence of debouncing is trying to access properties from the native event when a gesture has ended will probably result in a warning: React does event pooling, meaning a React event can only be queried synchronously.

Adding gestures to dom nodes

React-use-gesture also supports to add handlers to dom nodes directly (or the window or document objects). In that case, you shouldn't spread the bind() object returned by useGesture as a prop, but use the React.useEffect hook as below.

// this will add a scroll listener to the window
const bind = useGesture({ onScroll: state => doStuff }, { domTarget: window })
React.useEffect(bind, [bind])

Note that using useEffect will also take care of removing event listeners when the component is unmounted.

Shortcut to the drag event handler

Although React-use-gesture was initially developed to support drag events only (press, move and release), this library now supports pinch, hover, move, scroll and wheel events. To ensure retro-compatibility with v4.x, v5.x still gives you a shortcut to the onDrag and pass directly the handler function as the sole argument of useGesture

// This:
const bind = useGesture(state => doStuff)
// is equivalent to this:
const bind = useGesture({ onDrag: state => doStuff })

useGesture event state

Every time a handler is called, it will get passed the current event state for its corresponding gesture. An event state is an object that includes the source event and adds multiple attributes listed below.

Shared State

The following attributes are provided to the handler whatever the gesture.

Name	Type	Description
event	object	source event
time	Number	timestamp of the current gesture
first	Boolean	marks the first event
last	Boolean	marks the last event
active	Boolean	true when the gesture is active, false otherwise
temp	Any	serves as a cache storing any value returned by your handler during its previous run. See below for an example.
cancel	Function	you can call cancel to interrupt the drag gesture. cancelis only relevant in the onDrag handler.
down	Boolean	mouse / touch down
touches	Number	number of touches pressing the screen
shiftKey altKey ctrlKey metaKey	Boolean	modifier keys are pressed
dragging	Boolean	true when the user is dragging
moving	Boolean	true when the user is moving the mouse
hovering	Boolean	true when the mouse hovers the element
scrolling	Boolean	true when the user is scrolling
wheeling	Boolean	true when the user is wheeling
args	Any	arguments you passed to bind

Specific state attributes for XY Gestures [drag, scroll, wheel, hover]

The following attributes are provided to the handler for gestures that deal with x/y coordinates.

Name	Type	Description
xy	Vec2 ([x,y])	for touch/mouse events, xy returns the position of the pointer on the screen. For scroll/wheel events xy returns how much the element has been scrolled on x and y axis.
previous	Vec2	previous xy
initial	Vec2	xy value when the gesture has started
delta	Vec2	delta offset (xy - initial)
local	Vec2	delta with book-keeping (remembers the xy value throughout gestures)
lastLocal	Vec2	previous local
vxvy	Vec2	momentum / speed of the gesture (x and y axis separated)
velocity	Number	momentum / speed of the gesture (x and y axis combined)
distance	Number	delta distance

Specific state attributes for Distance Angle Gestures [pinch]

Pinch is generally about scaling and rotating. The scale depends on the distance between the two fingers, while the rotation depends on the direction / angle of the vector formed by the two fingers. Or more specifically, both scale and rotation depends on the delta of distance and angle, so you will probably end up using local or delta in most cases.

Name	Type	Description
da	Vec2	distance and angle.
previous	Vec2	previous da
initial	Vec2	da value when the gesture has started
delta	Vec2	delta offset (da - initial)
local	Vec2	delta with book-keeping (remembers the da value throughout gestures)
lastLocal	Vec2	previous local
vdva	Vec2	momentum / speed of the gesture for distance and angle
turns	Number	keeps track of the number of turns

useGesture config

You can pass a config object as an optional second argument to useGesture to customize its behavior.

Name	Default Value	Description
domTarget	undefined	lets you specify a dom node you want to attach gestures to (body, window, document...)
event	{passive: true, capture: false}	the event config attribute lets you configure passive and capture options passed to event listeners
transform	{x: x => x, y =>y }	transform functions you can pass to modify x and y values.
window	window	lets you specify which window element useGesture should use. See this thread for a relevant use case.
enabled	true	enables or disables all gestures
drag pinch scroll wheel hover move	true	enables or disables gestures individually

Examples

React hooks with onAction (and react-spring) (basic pull & release)

Demo: https://codesandbox.io/s/r24mzvo3q

React hooks with onAction (and react-spring) (decay)

Demo: https://codesandbox.io/s/zq19y1xr9m

This demo reads out further data like velocity and direction to calculate decay. temp in this case is a simple storage that picks up whatever value you (optionally) return inside the event handler. It's valid as long as the gesture is active. Without this you would need to store the initial xy value somewhere else and conditionally update it when the gesture begins.

const [{ xy }, set] = useSpring(() => ({ xy: [0, 0] }))
const bind = useGesture(({ down, delta, velocity, direction, temp = xy.getValue() }) => {
  set({
    xy: add(delta, temp),
    immediate: down,
    config: { velocity: scale(direction, velocity), decay: true }
  })
  return temp
})
return <animated.div {...bind()} style={{ transform: xy.interpolate((x, y) => `translate3d(${x}px,${y}px,0)`) }} />

Frequently asked questions

What are the differences between using useGesture and adding listeners manually? Not a lot! Essentially useGesture simplifies the implementation of the drag and pinch gestures, calculates kinematics values you wouldn't get out of the box from the listeners, and debounces move scroll and wheel events to let you know when they end.

How do you pass state to useGesture? The recommended way of passing an external value to useGesture is by using React.useRef.

Why onMove when onDrag already exists? onDrag only fires while your touch or press the element. You just need to hover your mouse above the element to trigger onMove.

Why onWheel and onScroll? Scrolling and wheeling are structurally different events although they produce similar results (i.e. scrolling a page). First of all, wheel is a mouse-only event. Then, for onScroll to be fired, the element you're scrolling needs to actually scroll, therefore have content overflowing, while you just need to wheel over an element to trigger onWheel. If you use react-three-fiber, onWheel might prove useful to simulate scroll on canvas elements.