code: function charset (type) {
    if (!type || typeof type !== 'string') {
      return false
    }
  
    // TODO: use media-typer
    var match = EXTRACT_TYPE_REGEXP.exec(type)
    var mime = match && db[match[1].toLowerCase()]
  
    if (mime && mime.charset) {
      return mime.charset
    }
  
    // default text/* to utf-8
    if (match && TEXT_TYPE_REGEXP.test(match[1])) {
      return 'UTF-8'
    }
  
    return false
  }
docs: Get the default charset for a MIME type.
  
  @param {string} type
  @return {boolean|string}