@teachorg/react-range

react-range

FORKED from https://github.com/tajo/react-range

See all the other examples and their source code!

Installation

yarn add react-range

Usage

import * as React from 'react';
import { Range } from 'react-range';

class SuperSimple extends React.Component {
  state = { values: [50] };
  render() {
    return (
      <Range
        step={0.1}
        min={0}
        max={100}
        values={this.state.values}
        onChange={values => this.setState({ values })}
        renderTrack={({ props, children }) => (
          <div
            {...props}
            style={{
              ...props.style,
              height: '6px',
              width: '100%',
              backgroundColor: '#ccc'
            }}
          >
            {children}
          </div>
        )}
        renderThumb={({ props }) => (
          <div
            {...props}
            style={{
              ...props.style,
              height: '42px',
              width: '42px',
              backgroundColor: '#999'
            }}
          />
        )}
      />
    );
  }
}

Features

• Range input supporting vertical and horizontal sliding
• Unopinionated styling, great for CSS in JS too
• No wrapping divs or additional markup, bring your own!
• Accessible, made for keyboards and screen readers
• Touchable, works on mobile devices
• Can handle negative and decimal values
• Stateless and controlled single component
• Typescript and Flow type definitions
• No dependencies, less than 4kB (gzipped)
• Coverage by e2e puppeteer tests
• RTL support

Keyboard support

• tab and shift+tab to focus thumbs
• arrow up or arrow right or k to increase the thumb value by one step
• arrow down or arrow left or j to decrease the thumb value by one step
• page up to increase the thumb value by ten steps
• page down to decrease the thumb value by ten steps

<Range /> props

renderTrack

renderTrack: (params: {
  props: {
    style: React.CSSProperties;
    ref: React.RefObject<any>;
    onMouseDown: (e: React.MouseEvent) => void;
    onTouchStart: (e: React.TouchEvent) => void;
  };
  children: React.ReactNode;
  isDragged: boolean;
  disabled: boolean;
}) => React.ReactNode;

renderTrack prop to define your track (root) element. Your function gets four parameters and should return a React component:

• props - this needs to be spread over the root track element, it connects mouse and touch events, adds a ref and some necessary styling
• children - the rendered thumbs, thumb structure should be specified in a different prop - renderThumb
• isDragged - true if any thumb is being dragged
• disabled - true if <Range disabled={true} /> is set

The track can be a single narrow div as in the Super simple example; however, it might be better to use at least two nested divs where the outter div is much thicker and has a transparent background and the inner div is narrow, has visible background and is centered. props should be then spread over the outter bigger div. Why to do this? It's nice to keep the onMouseDown and onTouchStart targets bigger since the thumb can be moved also by clicking on the track (in a single thumb scenario).

renderThumb

renderThumb: (params: {
  props: {
    key: number;
    style: React.CSSProperties;
    tabIndex?: number;
    'aria-valuemax': number;
    'aria-valuemin': number;
    'aria-valuenow': number;
    draggable: boolean;
    role: string;
    onKeyDown: (e: React.KeyboardEvent) => void;
    onKeyUp: (e: React.KeyboardEvent) => void;
  };
  value: number;
  index: number;
  isDragged: boolean;
}) => React.ReactNode;

renderThumb prop to define your thumb. Your function gets four parameters and should return a React component:

• props - it has multiple props that you need to spread over your thumb element
• value - a number, relative value based on min, max, step and the thumb's position
• index - the thumb index (order)
• isDragged - true if the thumb is dragged, great for styling purposes

values

values: number[];

An array of numbers. It controls the position of thumbs on the track. values.length equals to the number of rendered thumbs.

onChange

onChange: (values: number[]) => void;

Called when a thumb is moved, provides new values.

onFinalChange

onFinalChange: (values: number[]) => void;

Called when a change is finished (mouse/touch up, or keyup), provides current values. Use this event when you have to make for example ajax request with new values.

min (optional)

min: number;

The range start. Can be decimal or negative. Default is 0.

max (optional)

max: number;

The range end. Can be decimal or negative. Default is 100.

step (optional)

step: number;

The minimal distance between two values. Can be decimal. Default is 1.

allowOverlap (optional)

allowOverlap: boolean;

When there are multiple thumbs on a single track, should they be allowed to overlap? Default is false.

direction (optional)

direction: Direction;

enum Direction {
  Right = 'to right',
  Left = 'to left',
  Down = 'to bottom',
  Up = 'to top'
}

It sets the orientation (vertical vs horizontal) and the direction in which the value increases. You can get this enum by:

import { Direction } from 'react-range';

Default value is Direction.Right.

disabled (optional)

disabled: boolean;

If true, it ignores all touch and mouse events and makes the component not focusable. Default is false.

rtl (optional)

rtl: boolean;

If true, the slider will be optimized for RTL layouts. Default is false.

getTrackBackground

There is an additional helper function being exported from react-range. Your track is most likely a div with some background. What if you want to achieve a nice "progress bar" effect where the part before the thumb has different color than the part after? What if you want to have the same thing even with multiple thumbs (aka differently colored segments)? You don't need to glue together multiple divs in order to do that! You can use a single div and set background: linear-gradient(...). getTrackBackground function builds this verbose linear-gradient(...) for you!

getTrackBackground: (params: {
  min: number;
  max: number;
  values: number[];
  colors: string[];
  direction?: Direction;
  rtl?: boolean;
}) => string;

min, max, values and direction should be same as for the <Range /> component. colors is a list of colors. This needs to be true:

values.length + 1 === colors.length;

That's because one thumb (one value) splits the track into two segments, so you need two colors.

Motivation

There is a native input solution:

<input type="range" />

However, it has some serious shortcomings:

• vertical-oriented slider is not supported in all browsers
• supports only a single direction
• very limited styling options
• no support for multiple thumbs

There are also many React based solutions but most of them are too bloated, don't support styling through CSS in JS or have lacking performance.

react-range has two main goals:

• Small footprint - less then 4kB gzipped, single component.
• Bring your own styles and HTML markup - react-range is a more low-level approach than other libraries. It doesn't come with any styling (except some positioning) or markup. It's up to the user to specify both! Think about react-range as a foundation for other styled input ranges.

End to end testing

This library is tightly coupled to many DOM APIs. It would be very hard to ensure 100% test coverage just with unit tests that would not involve a lot of mocking. Or we could re-architect the library to better abstract all DOM interfaces but that would mean more code and bigger footprint.

Instead of that, react-range adds thorough end to end tests powered by puppeteer.

All tests are automatically ran in Travis CI with headless chromium. This way, the public API is well tested, including pixel-perfect positioning. Also, the tests are pretty fast, reliable and very descriptive.

Do you want to run them in the dev mode (slows down operations, opens the browser)?

yarn storybook #start the storybook server
yarn test:e2e:dev #run the e2e tests

CI mode (storybook started on the background, quick, headless)

yarn test:e2e

Browser support

• Chrome (latest, mac, windows, iOS, Android)
• Firefox (latest, mac, windows)
• Safari (latest, mac, iOS)
• Edge (latest, windows)
• MSIE 11 (windows)

Contributing

This is how you can spin up the dev environment:

git clone https://github.com/tajo/react-range
cd react-range
yarn
yarn storybook

Shoutouts 🙏

Big big shoutout to Tom MacWright for donating the react-range npm handle! ❤️

Big thanks to BrowserStack for letting the maintainers use their service to debug browser issues.

Author

Vojtech Miksu 2019, miksu.cz, @vmiksu