audio-fx-es6.js

/* es6-yfied https://github.com/jakesgordon/javascript-audio-fx */

export default class AudioFX {
  constructor(src, options = {}, onload = () => {}) {
    this.detectCapabilities();

    let formats = options.formats || [];
    let format  = this.choose(formats);
    this.pool = [];

    src = src + (format ? '.' + format : '');

    if (this.hasAudio) {
      for (let n = 0 ; n < (options.pool || 1) ; n++) {
        let audio = this.create(src, options, n === 0 ? onload : null);
        this.pool.push(audio);
      }
    } else {
      onload();
    }

    this.audio = (this.pool.length === 1) ? this.pool[0] : this.pool;
  }

  play() {
    let audio = this.find(this.pool);
    if (audio) { audio.play(); }
  }

  stop() {
    for (let n = 0 ; n < this.pool.length ; n++) {
      let audio = this.pool[n];
      audio.pause();
      audio.currentTime = 0;
    }
  }

  choose(formats) {
    for (let n = 0 ; n < formats.length ; n++) {
      if (this.hasAudio && this.hasAudio[formats[n]]) {
        return formats[n];
      }
    }
  }

  find(audios) {
    for (let n = 0 ; n < audios.length ; n++) {
      let audio = audios[n];
      if (audio.paused || audio.ended) {
        return audio;
      }
    }
  }

  audioSupported(audio, type) {
    let s = audio.canPlayType(type);
    return (s === 'probably') || (s === 'maybe');
  }

  detectCapabilities() {
    let audio = document.createElement('audio');

    if (audio && audio.canPlayType) {
      this.hasAudio = {
        ogg: this.audioSupported(audio, 'audio/ogg; codecs="vorbis"'),
        mp3: this.audioSupported(audio, 'audio/mpeg;'),
        m4a: this.audioSupported(audio, 'audio/x-m4a;') || this.audioSupported(audio, 'audio/aac;'),
        wav: this.audioSupported(audio, 'audio/wav; codecs="1"'),
        loop: (typeof audio.loop === 'boolean') // some browsers (FF) dont support loop yet
      };
    } else {
      this.hasAudio = false;
    }
  }

  create(src, options, onload) {
    let audio = document.createElement('audio');

    if (onload) {
      let ready = function() {
        audio.removeEventListener('canplay', ready, false);
        onload();
      };

      audio.addEventListener('canplay', ready, false);
    }

    if (options.loop && !this.hasAudio.loop) {
      audio.addEventListener('ended', function() {
        audio.currentTime = 0; audio.play();
      }, false);
    }

    audio.volume = options.volume || 0.1;
    audio.autoplay = options.autoplay;
    audio.loop = options.loop;
    audio.src = src;

    return audio;
  }
}