This content originally appeared on DEV Community and was authored by Uralys

How to play audio with React

In this article, I’ll show you how I play audio in my React frontends.

Previously in this article I set up a list of Lottie animations displaying a music track being played when the user hovers the area.

I now need to play an audio at the same time.

setting up the audio

I have 4 audio files somewhere on S3, distributed by CloudFront:

const musics = [
  'https://alterego.community/audio/classique.mp4',
  'https://alterego.community/audio/folk.mp4',
  'https://alterego.community/audio/electro.mp4',
  'https://alterego.community/audio/hip-hop.mp4'
];

For each music, I create an audio element and load it on mount:

const [audio, setAudio] = useState<HTMLAudioElement>();

useEffect(() => {
  const _audio = new Audio(musics[props.num - 1]);
  _audio.load();
  _audio.addEventListener('canplaythrough', () => {
    setAudio(_audio);
  });
}, []);

Listening for the user’s interaction

I add a React ref on a parent element of the Lottie animation to listen for hover and touch events:

const musicRef = useRef<HTMLDivElement>(null);

<$Music ref={musicRef}>
  <Lottie hover loop={true} src={musicAnimation} />
</$Music>

Now when audio is ready, I can listen for the user’s interaction:

useEffect(() => {
  if (!audio) return;
  if (!musicRef) return;

  const play = async () => {
    audio.play();
  };

  const stop = () => {
    audio.pause();
    audio.currentTime = 0;
  };

  const element = musicRef.current;

  if (element) {
    element.addEventListener('mouseenter', play);
    element.addEventListener('mouseleave', stop);
    element.addEventListener('touchstart', play);
    element.addEventListener('touchend', stop);

    return () => {
      element.removeEventListener('mouseenter', play);
      element.removeEventListener('mouseleave', stop);
      element.removeEventListener('touchstart', play);
      element.removeEventListener('touchend', stop);
    };
  }
}, [musicRef, audio]);

Plugging the state

We need to store the selected music in the state.

I handle the state the same way I did in the article about La Taverne:

The action + reducing in my barrel:

export const PICK_MUSIC = '@@user/PICK_MUSIC';

type PickMusicPayload = {musicChoice: MusicChoice};

export type PickMusicAction = {
  type: '@@user/PICK_MUSIC';
  payload: PickMusicPayload;
};

const onPickMusic = {
  on: PICK_MUSIC,
  reduce: (state: State, payload: PickMusicPayload) => {
    const {musicChoice} = payload;
    state.preferredMusic = musicChoice;
  }
};

Then the React part:

import {useTaverne} from 'taverne/hooks';

// ... in the component:

const {dispatch, pour} = useTaverne();
const preferredMusic = (pour('user.preferredMusic') || -1) as MusicChoice;

const pickMusic = (musicChoice: MusicChoice) => () => {
  dispatch({
    type: PICK_MUSIC,
    payload: {musicChoice}
  } as PickMusicAction);
};

<Music
  num={musicNum}
  selected={preferredMusic === musicNum}
  onClick={pickMusic(musicNum)}
/>

Mounting it all together

then in the parent component rendering all musics:

type MusicChoice = -1 | 1 | 2 | 3 | 4;
const musicChoices: Array<MusicChoice> = [1, 2, 3, 4];

<$Musics>
  {musicChoices.map(musicNum => (
    <Music
      key={`music-${musicNum}`}
      num={musicNum}
      selected={preferredMusic === musicNum}
      onClick={pickMusic(musicNum)}
    />
  ))}
</$Musics>

Thanks for reading, see you around!

As always, feel free to comment on parts you need more explanations for, or share your thoughts on how you would have handled the parts you disagree with.

This content originally appeared on DEV Community and was authored by Uralys