code: function normalize (type) {
    if (typeof type !== 'string') {
      // invalid type
      return false
    }
  
    switch (type) {
      case 'urlencoded':
        return 'application/x-www-form-urlencoded'
      case 'multipart':
        return 'multipart/*'
    }
  
    if (type[0] === '+') {
      // "+json" -> "*/*+json" expando
      return '*/*' + type
    }
  
    return type.indexOf('/') === -1
      ? mime.lookup(type)
      : type
  }
docs: Normalize a mime type.
  If it's a shorthand, expand it to a valid mime type.
  
  In general, you probably want:
  
  var type = is(req, ['urlencoded', 'json', 'multipart']);
  
  Then use the appropriate body parsers.
  These three are the most common request body types
  and are thus ensured to work.
  
  @param {String} type
  @private