code: function parse (string) {
    if (typeof string !== 'string') {
      return undefined
    }
  
    // parse header
    var match = CREDENTIALS_REGEXP.exec(string)
  
    if (!match) {
      return undefined
    }
  
    // decode user pass
    var userPass = USER_PASS_REGEXP.exec(decodeBase64(match[1]))
  
    if (!userPass) {
      return undefined
    }
  
    // return credentials object
    return new Credentials(userPass[1], userPass[2])
  }
docs: Parse basic auth to object.
  
  @param {string} string
  @return {object}
  @public