typescript-logging/src/logging/log/standard/LogGroupRule.ts

Library for logging, written in typescript, can be used by normal es5+ javascript as well.

import {Logger} from "./Logger";
import {LogFormat, LoggerType, LogLevel} from "../LoggerOptions";
import {LogMessage} from "./AbstractLogger";
import {LogGroupRuntimeSettings} from "./LogGroupRuntimeSettings";

/**
 * Defines a LogGroupRule, this allows you to either have everything configured the same way
 * or for example loggers that start with name model. It allows you to group loggers together
 * to have a certain loglevel and other settings. You can configure this when creating the
 * LoggerFactory (which accepts multiple LogGroupRules).
 */
export class LogGroupRule {

  private _regExp: RegExp;
  private _level: LogLevel;
  private _loggerType: LoggerType;
  private _logFormat: LogFormat;
  private _callBackLogger: ((name: string, settings: LogGroupRuntimeSettings) => Logger) | null;
  private _formatterLogMessage: ((message: LogMessage) => string) | null = null;

  /**
   * Create a LogGroupRule. Basically you define what logger name(s) match for this group, what level should be used what logger type (where to log)
   * and what format to write in. If the loggerType is custom, then the callBackLogger must be supplied as callback function to return a custom logger.
   * @param regExp Regular expression, what matches for your logger names for this group
   * @param level LogLevel
   * @param logFormat LogFormat
   * @param loggerType Type of logger, if Custom, make sure to implement callBackLogger and pass in, this will be called so you can return your own logger.
   * @param callBackLogger Callback function to return a new clean custom logger (yours!)
   */
  constructor(regExp: RegExp, level: LogLevel, logFormat: LogFormat = new LogFormat(),
              loggerType: LoggerType = LoggerType.Console,
              callBackLogger: ((name: string, settings: LogGroupRuntimeSettings) => Logger) | null = null) {
    this._regExp = regExp;
    this._level = level;
    this._logFormat = logFormat;
    this._loggerType = loggerType;
    this._callBackLogger = callBackLogger;
  }

  get regExp(): RegExp {
    return this._regExp;
  }

  get level(): LogLevel {
    return this._level;
  }

  get loggerType(): LoggerType {
    return this._loggerType;
  }

  get logFormat(): LogFormat {
    return this._logFormat;
  }

  get callBackLogger(): ((name: string, settings: LogGroupRuntimeSettings) => Logger) | null {
    return this._callBackLogger;
  }

  /**
   * Get the formatterLogMessage function, see comment on the setter.
   * @returns {((message:LogMessage)=>string)|null}
   */
  get formatterLogMessage(): ((message: LogMessage) => string) | null {
    return this._formatterLogMessage;
  }

  /**
   * Set the default formatterLogMessage function, if set it is applied to all type of loggers except for a custom logger.
   * By default this is null (not set). You can assign a function to allow custom formatting of a log message.
   * Each log message will call this function then and expects your function to format the message and return a string.
   * Will throw an error if you attempt to set a formatterLogMessage if the LoggerType is custom.
   * @param value The formatter function, or null to reset it.
   */
  set formatterLogMessage(value: ((message: LogMessage) => string) | null) {
    if (value !== null && this._loggerType === LoggerType.Custom) {
      throw new Error("You cannot specify a formatter for log messages if your loggerType is Custom");
    }
    this._formatterLogMessage = value;
  }
}