web-audio-player/lib/can-play-src.js

a cross-browser WebAudio player

var lookup = require('browser-media-mime-type')
var audio

module.exports = isSrcPlayable
function isSrcPlayable (src) {
  if (!src) throw new TypeError('src cannot be empty')
  var type
  if (typeof src.getAttribute === 'function') {
    // <source> element
    type = src.getAttribute('type')
  } else if (typeof src === 'string') {
    // 'foo.mp3' string
    var ext = extension(src)
    if (ext) type = lookup(ext)
  } else {
    // { src: 'foo.mp3', type: 'audio/mpeg; codecs..'}
    type = src.type
  }

  // We have an unknown file extension or
  // a <source> tag without an explicit type,
  // just let the browser handle it!
  if (!type) return true

  // handle "no" edge case with super legacy browsers...
  // https://groups.google.com/forum/#!topic/google-web-toolkit-contributors/a8Uy0bXq1Ho
  if (!audio) audio = new window.Audio()
  var canplay = audio.canPlayType(type).replace(/no/, '')
  return Boolean(canplay)
}

module.exports.createError = createError
function createError (sources) {
  // All sources are unplayable
  var err = new Error('This browser does not support any of the following sources:\n    ' +
      sources.join(', ') + '\n' +
      'Try using an array of OGG, MP3 and WAV.')
  err.type = 'AUDIO_FORMAT'
  return err
}

function extension (data) {
  var extIdx = data.lastIndexOf('.')
  if (extIdx <= 0 || extIdx === data.length - 1) {
    return undefined
  }
  return data.substring(extIdx + 1)
}