@zcodeapp/logger NPM

Logger

Overview

This TypeScript Logger class is part of the @zcodeapp packages. It offers a flexible logging system with support for different logging strategies and levels.

Features

Singleton pattern with getInstance method.
Configurable logging levels (DEBUG, INFO, WARN, ERROR, FATAL).
Customizable logging strategies.
Prefix addition to log messages.

Installation

Include the Logger class in your TypeScript project:

npm install @zcodeapp/logger

Usage

First, import the Logger class and other necessary interfaces:

import { Logger, ELoggerLevel, ILoggerOptions, LoggerStrategyConsole } from "@zcodeapp/interfaces";

Then, configure and use the logger:

// Configure Logger
const loggerOptions: ILoggerOptions = {
  level: ELoggerLevel.DEBUG,
  strategy: new LoggerStrategyConsole(),
  // other options...
};
const logger = Logger.getInstance(loggerOptions);

// Use Logger
logger.debug("Debug message");
logger.info("Info message");
logger.warn("Warning message");
logger.error("Error message");
logger.fatal("Fatal message");

API Reference

Logger.getInstance(options?: ILoggerOptions): ILogger Returns a singleton instance of the Logger. If options is provided, it configures the logger accordingly.

configure(options: ILoggerOptions): void Configures the logger with the given options.

getOptions(): ILoggerOptions Returns the current logger options.

addPrefix(prefix: string): void Adds a prefix to all log messages.

Logging Methods

debug(message: string, params?: any): void
info(message: string, params?: any): void
warn(message: string, params?: any): void
error(message: string, params?: any): void
fatal(message: string, params?: any): void

`ILoggerOptions` Reference

ILoggerOptions is an interface that provides various configuration options for the Logger. Below are the details of each option available:

level (ELoggerLevel): This option sets the logging level for the logger. The available levels are:
- DEBUG: Logs detailed information, primarily useful for developers.
- INFORMATION: Logs informative messages that highlight the progress of the application.
- WARNING: Logs potentially harmful situations.
- ERROR: Logs error events that might still allow the application to continue running.
- FATAL: Logs severe error events that presumably lead the application to abort.
strategy: Defines the strategy for logging messages. This can be an instance of any class that implements the logging strategy, like LoggerStrategyConsole. The strategy default determines how and where the log messages are outputted.
prefix (string): An optional string that is prepended to every log message. This is useful for tagging logs with specific identifiers like module names or environment names.
newInstance (boolean): An optional flag to create a new logger instance instead of using the singleton pattern. By default, Logger uses a singleton pattern, and this flag is set to false.

Example

Here's an example of how to configure the Logger with ILoggerOptions:

const options: ILoggerOptions = {
  level: ELoggerLevel.DEBUG,
  strategy: new LoggerStrategyConsole(),
  prefix: "MyApp",
  newInstance: true
};

const logger = Logger.getInstance(options);
logger.info("Application started");