use-media

use-media

useMedia React sensor hook that tracks state of a CSS media query.

Usage

With useEffect

import useMedia from 'use-media';
// Alternatively, you can import as:
// import {useMedia} from 'use-media';

const Demo = () => {
  // Accepts an object of features to test
  const isWide = useMedia({minWidth: 1000});
  // Or a regular media query string
  const reduceMotion = useMedia('(prefers-reduced-motion: reduce)');

  return (
    <div>
      Screen is wide: {isWide ? '😃' : '😢'}
    </div>
  );
};

With useLayoutEffect

import {useMediaLayout} from 'use-media';

const Demo = () => {
  // Accepts an object of features to test
  const isWide = useMediaLayout({minWidth: 1000});
  // Or a regular media query string
  const reduceMotion = useMediaLayout('(prefers-reduced-motion: reduce)');

  return (
    <div>
      Screen is wide: {isWide ? '😃' : '😢'}
    </div>
  );
};

Testing

Depending on your testing setup, you may need to mock window.matchMedia on components that utilize the useMedia hook. Below is an example of doing this in jest:

/test-utilities/index.ts

import {mockMediaQueryList} from 'use-media/lib/useMedia';
// Types are also exported for convienence:
// import {Effect, MediaQueryObject} from 'use-media/lib/types';

export interface MockMatchMedia {
  media: string;
  matches?: boolean;
}

function getMockImplementation({media, matches = false}: MockMatchMedia) {
  const mql: MediaQueryList = {
    ...mockMediaQueryList,
    media,
    matches,
  };

  return () => mql;
}

export function jestMockMatchMedia({media, matches = false}: MockMatchMedia) {
  const mockedImplementation = getMockImplementation({media, matches});
  window.matchMedia = jest.fn().mockImplementation(mockedImplementation);
}

/components/MyComponent/MyComponent.test.tsx

const mediaQueries = {
  mobile: '(max-width: 767px)',
  prefersReducedMotion: '(prefers-reduced-motion: reduce)',
};

describe('<MyComponent />', () => {
  const defaultProps: Props = {
    duration: 100,
  };

  afterEach(() => {
    jestMockMatchMedia({
      media: mediaQueries.prefersReducedMotion,
      matches: false,
    });
  });

  it('sets `duration` to `0` when user-agent `prefers-reduced-motion`', () => {
    jestMockMatchMedia({
      media: mediaQueries.prefersReducedMotion,
      matches: true,
    });

    const wrapper = mount(<MyComponent {...defaultProps} />);
    const child = wrapper.find(TransitionComponent);

    expect(child.prop('duration')).toBe(0);
  });
});

Storing in Context

Depending on your app, you may be using the useMedia hook to register many matchMedia listeners across multiple components. It may help to elevate these listeners to Context.

/components/MediaQueryProvider/MediaQueryProvider.tsx

import React, {createContext, useContext, useMemo} from 'react';
import useMedia from 'use-media';

interface Props {
  children: React.ReactNode;
}

export const MediaQueryContext = createContext(null);

const mediaQueries = {
  mobile: '(max-width: 767px)',
  prefersReducedMotion: '(prefers-reduced-motion: reduce)',
};

export default function MediaQueryProvider({children}: Props) {
  const mobileView = useMedia(mediaQueries.mobile);
  const prefersReducedMotion = useMedia(mediaQueries.prefersReducedMotion);
  const value = useMemo(() => ({mobileView, prefersReducedMotion}), [
    mobileView,
    prefersReducedMotion,
  ]);

  return (
    <MediaQueryContext.Provider value={value}>
      {children}
    </MediaQueryContext.Provider>
  );
}

export function useMediaQueryContext() {
  return useContext(MediaQueryContext);
}

/components/App/App.tsx

import React from 'react';
import MediaQueryProvider from '../MediaQueryProvider';
import MyComponent from '../MyComponent';

export default function App() {
  return (
    <MediaQueryProvider>
      <div id="MyApp">
        <MyComponent />
      </div>
    </MediaQueryProvider>
  );
}

/components/MyComponent/MyComponent.tsx

import React from 'react';
import {useMediaQueryContext} from '../MediaQueryProvider';

export default function MyComponent() {
  const {mobileView, prefersReducedMotion} = useMediaQueryContext();

  return (
    <div>
      <p>mobileView: {Boolean(mobileView).toString()}</p>
      <p>prefersReducedMotion: {Boolean(prefersReducedMotion).toString()}</p>
    </div>
  );
}

Changelog

1.4.0 (2019-07-27)

Features

• refactor /src folder (8f72ba2)