CachedAudio.js

import { StatusBar } from 'react-native';
import { Audio, FileSystem } from 'expo';

export default class CachedAudio {
  constructor(uri) {
    this.uri = uri;
    this.fileUri = null;
    this.sound = null;
    this.downloadResumable = null;
  }

  async _downloadAsync() {
    this.fileUri = `${FileSystem.cacheDirectory}${encodeURIComponent(encodeURIComponent(this.uri))}`;
    const { exists } = await FileSystem.getInfoAsync(this.fileUri);

    if (exists) {
      return;
    }

    this.downloadResumable = FileSystem.createDownloadResumable(
      this.uri,
      this.fileUri,
    );

    StatusBar.setNetworkActivityIndicatorVisible(true);
    try {
      const { uri } = await this.downloadResumable.downloadAsync();
      this.fileUri = uri;
      this.downloadResumable = null;
    } finally {
      StatusBar.setNetworkActivityIndicatorVisible(false);
    }
  }

  async _createAsync() {
    const { sound } = await Audio.Sound.create({ uri: this.fileUri });
    this.sound = sound;
  }

  async playAsync() {
    if (!this.fileUri) {
      await this._downloadAsync();
    }

    if (!this.sound) {
      await this._createAsync();
    }

    const { positionMillis, durationMillis } = await this.sound.getStatusAsync();
    if (positionMillis === durationMillis) {
      await this.sound.replayAsync();
    } else {
      await this.sound.playAsync();
    }

    return this.sound;
  }

  async pauseAsync() {
    if (!this.sound) {
      return;
    }

    await this.sound.pauseAsync();
  }

  async unloadAsync() {
    if (this.downloadResumable) {
      await this.downloadResumable.pauseAsync();
    }

    if (this.sound) {
      this.sound.setOnPlaybackStatusUpdate(null);
      await this.sound.unloadAsync();
    }
  }
};