nypublicradio/ember-hifi

// we are only concerned with a subset of all available mime types
// data and function lifted from https://github.com/jshttp/mime-db
const MIME_TYPES = {
  "audio/3gpp": {
    "source": "iana",
    "extensions": ["3gpp"]
  },
  "audio/adpcm": {
    "source": "apache",
    "extensions": ["adp"]
  },
  "audio/aac": {
    "compressible": false,
    "extensions": ["aac"]
  },
  "audio/basic": {
    "source": "iana",
    "compressible": false,
    "extensions": ["au","snd"]
  },
  "audio/midi": {
    "source": "apache",
    "extensions": ["mid","midi","kar","rmi"]
  },
  "audio/mp3": {
    "compressible": false,
    "extensions": ["mp3"]
  },
  "audio/mp4": {
    "source": "iana",
    "compressible": false,
    "extensions": ["m4a","mp4a"]
  },
  "audio/mpeg": {
    "source": "iana",
    "compressible": false,
    "extensions": ["mpga","mp2","mp2a","mp3","m2a","m3a"]
  },
  "audio/ogg": {
    "source": "iana",
    "compressible": false,
    "extensions": ["oga","ogg","spx"]
  },
  "audio/s3m": {
    "source": "apache",
    "extensions": ["s3m"]
  },
  "audio/silk": {
    "source": "apache",
    "extensions": ["sil"]
  },
  "audio/vnd.dece.audio": {
    "source": "iana",
    "extensions": ["uva","uvva"]
  },
  "audio/vnd.digital-winds": {
    "source": "iana",
    "extensions": ["eol"]
  },
  "audio/vnd.dra": {
    "source": "iana",
    "extensions": ["dra"]
  },
  "audio/vnd.dts": {
    "source": "iana",
    "extensions": ["dts"]
  },
  "audio/vnd.dts.hd": {
    "source": "iana",
    "extensions": ["dtshd"]
  },
  "audio/vnd.lucent.voice": {
    "source": "iana",
    "extensions": ["lvp"]
  },
  "audio/vnd.ms-playready.media.pya": {
    "source": "iana",
    "extensions": ["pya"]
  },
  "audio/vnd.nuera.ecelp4800": {
    "source": "iana",
    "extensions": ["ecelp4800"]
  },
  "audio/vnd.nuera.ecelp7470": {
    "source": "iana",
    "extensions": ["ecelp7470"]
  },
  "audio/vnd.nuera.ecelp9600": {
    "source": "iana",
    "extensions": ["ecelp9600"]
  },
  "audio/vnd.rip": {
    "source": "iana",
    "extensions": ["rip"]
  },
  "audio/wav": {
    "compressible": false,
    "extensions": ["wav"]
  },
  "audio/wave": {
    "compressible": false,
    "extensions": ["wav"]
  },
  "audio/webm": {
    "source": "apache",
    "compressible": false,
    "extensions": ["weba"]
  },
  "audio/x-aiff": {
    "source": "apache",
    "extensions": ["aif","aiff","aifc"]
  },
  "audio/x-caf": {
    "source": "apache",
    "compressible": false,
    "extensions": ["caf"]
  },
  "audio/x-flac": {
    "source": "apache",
    "extensions": ["flac"]
  },
  "audio/x-m4a": {
    "source": "nginx",
    "extensions": ["m4a"]
  },
  "audio/x-matroska": {
    "source": "apache",
    "extensions": ["mka"]
  },
  "audio/x-mpegurl": {
    "source": "apache",
    "extensions": ["m3u"]
  },
  "audio/x-ms-wax": {
    "source": "apache",
    "extensions": ["wax"]
  },
  "audio/x-ms-wma": {
    "source": "apache",
    "extensions": ["wma"]
  },
  "audio/x-pn-realaudio": {
    "source": "apache",
    "extensions": ["ram","ra"]
  },
  "audio/x-pn-realaudio-plugin": {
    "source": "apache",
    "extensions": ["rmp"]
  },
  "audio/x-realaudio": {
    "source": "nginx",
    "extensions": ["ra"]
  },
  "audio/x-wav": {
    "source": "apache",
    "extensions": ["wav"]
  },
  "audio/xm": {
    "source": "apache",
    "extensions": ["xm"]
  },
  "application/vnd.apple.mpegurl": {
    "source": "iana",
    "extensions": ["m3u8"]
  },
  "audio/x-mpepgurl": {
    "source": "apache",
    "extensions": ["m3u"]
  }
};

const TYPES       = Object.create(null);
const EXTENSIONS  = Object.create(null);

function populateMaps(extensions, types) {
  // source preference (least -> most)
  let preference = ['nginx', 'apache', undefined, 'iana'];

  Object.keys(MIME_TYPES).forEach(function(type) {
    let mime = MIME_TYPES[type];
    let exts = mime.extensions;

    if (!exts || !exts.length) {
      return false;
    }

    // mime -> extensions
    extensions[type] = exts;

    // extension -> mime
    for (let i = 0; i < exts.length; i++) {
      let extension = exts[i];

      if (types[extension]) {
        let start = preference.indexOf(MIME_TYPES[types[extension]].source);
        let end = preference.indexOf(mime.source);

        if (types[extension] !== 'application/octet-stream' &&
          start > end || (start === end && types[extension].substr(0, 12) === 'application/')) {
          // skip the remapping
          continue;
        }
      }

      // set the extension -> mime
      types[extension] = type;
    }
  });
}

populateMaps(EXTENSIONS, TYPES);

export function getMimeType(url) {
  if (!url || typeof url !== 'string') {
    return false;
  }

  let extension = url
    .toLowerCase()
    .split('.').pop()
    .split('?').shift()
    .split('#').shift();

  if (!extension) {
    return false;
  }

  return TYPES[extension] || false;
}