code: function setLogLevel (val) {
    // update logger
    var logLevelEnum = LOG_STRING_TO_ENUM[val]
    if (logLevelEnum) {
      // set log level
      log.setLevel(logLevelEnum)
      configs.logLevel = val
    } else {
      // handle error
      var errorMessage = 'Unknown log level "' + val + '". Possible are: "' + Object.keys(LOG_STRING_TO_ENUM).join('", "') + '". '
      if (configs.logLevel) {
        // do not change current log level
        errorMessage += 'Log level remains "' + configs.logLevel
      } else {
        // set default log level
        var defaultVal = defaults.logLevel
        errorMessage += 'Fallback to default "' + defaultVal + '".'
        log.setLevel(LOG_STRING_TO_ENUM[defaultVal])
        configs.logLevel = defaultVal
      }
      console.error(errorMessage)
    }
  }
docs: private methods