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What is it?

A simpler Log4j inspired logger module for Angular 2. Think of it as "Log4ng" ... get it?

This is a work in progress and is not ready for production, use with care, the API can and will change.



  1. Install the npm module.

    npm install --save angular2-logger

  2. Add the angular2-logger library to your app. If you are following the Angular 2's Quickstart Guide it should be something like this:

    In systemjs.config.js:

     // map tells the System loader where to look for things
     var map = {
     	'app':                        'app', // 'dist',
     	'@angular':                   'node_modules/@angular',
     	'angular2-in-memory-web-api': 'node_modules/angular2-in-memory-web-api',
     	'rxjs':                       'node_modules/rxjs',
     	'angular2-logger':            'node_modules/angular2-logger' // ADD THIS
     //packages tells the System loader how to load when no filename and/or no extension
     var packages = {
     	'app':                        { main: 'main.ts',  defaultExtension: 'ts' },
     	'rxjs':                       { defaultExtension: 'js' },
     	'angular2-in-memory-web-api': { defaultExtension: 'js' },
     	'angular2-logger':            { defaultExtension: 'js' }, // AND THIS
  3. Setup the Provider.

    In app.module.ts:

     import { NgModule }      from '@angular/core';
     import { BrowserModule } from '@angular/platform-browser';
     import { AppComponent }  from './app.component';
     import { Logger } from "angular2-logger/core"; // ADD THIS
         imports:      [ BrowserModule ],
         declarations: [ AppComponent ],
         bootstrap:    [ AppComponent ],
         providers:    [ Logger ] // AND THIS
     export class AppModule { }
  4. Inject the logger into your objects and use it.

     export class AppComponent(){
     	constructor( private _logger: Logger ){
     		this._logger.error('This is a priority level 1 error message...');
     		this._logger.warn('This is a priority level 2 warning message...');'This is a priority level 3 warning message...');
     		this._logger.debug('This is a priority level 4 debug message...');
     		this._logger.log('This is a priority level 5 log message...');

By default the logger level will be set to Level.WARN, so you'll only see Warning and Error messages.

Going deeper...

In order to see all of the messages you just need to change the logger message hierarchy level, you can do so:

  • Dynamically using the console:

      logger.level = logger.Level.LOG; // same as: logger.level = 5;      
  • Or using one of the predefined configuration providers:

      import {LOG_LOGGER_PROVIDERS} from "angular2-logger/core";
          providers:    [ LOG_LOGGER_PROVIDERS ]
      export class AppModule { }

    The available Providers are:


Note: If you change the level of the Logger dynamically, that setting will be lost upon refreshing the page and set back to its default configured setting. If you want the logger to keep this setting changed, store it in the localStorage by doing: // and logger.unstore() to undo.

Custom Configuration

If the Providers included don't meet your needs you can configure the default logger configuration by Providing custom properties:

import { Logger, Options } from "angular2-logger/core";

    providers:    [ 
        { provide: Options, useValue: { store: false } },
export class AppModule { }

As you can see you don't have to specify all of them, just the ones you want to override.

The available configuration options are:

  • level:Level - How much detail you want to see in the logs; Level.ERROR (1) being the less detailed and Level.LOG (5) being the most. Defaults to Level.WARN (2).

    The Hierarchy of the messages is as follows from highest to lowest priority:

    0.- Level.OFF

    1.- Level.ERROR

    2.- Level.WARN

    3.- Level.INFO

    4.- Level.DEBUG

    5.- Level.LOG

    The Logger will log everything with higher or equal priority to the current logger.level set.

  • global:boolean - Whether or not you want the created logger object to be exposed in the global scope. Defaults to true.

  • globalAs:string - The window's property name that will hold the logger object created. Defaults to 'logger'.

  • store:boolean - Whether you want the level config to be saved in the local storage so it doesn't get lost when you refresh. Defaults to false.

  • storeAs:string - The local storage key that will be used to save the level config if the store setting is true. Defaults to 'angular2.logger.level'.

You can also override the default configuration options by extending the Options and injecting yours instead:

// from custom-logger-options.ts
@Injectable() export class CustomLoggerOptions(){
    store: true

// from app.module.ts
    providers:    [ 
        { provide: Options, useClass: CustomLoggerOptions },

Class names like Options and Level might be too common, if you get a conflict you can rename them like this:

import { Logger, Options as LoggerOptions, Level as LoggerLevel } from "angular2-logger/core";

    providers:    [ 
        { provide: LoggerOptions, useValue: { level: LoggerLevel.WARN } }

How you can help

Filing issues is helpful but pull requests are even better!

Instructions for dev environment

They are too long so try to keep up, here we go:

git clone

cd angular2-logger

npm i



  • Add a Level.OFF that turns off the logger.
  • Support different loaders and modes.
  • Add a basic demo.
  • Minify bundle.
  • Ability to add logging time to the messages.
  • Lazy Logging.
  • Appenders.
  • Support named loggers.
  • Message Layout Feature.
  • No coding required Dashboard UI to handle loggers.
  • Automatize definition files. Waiting for .

Breaking changes on 0.4.0

The codebase was updated to handle the breaking changes on Angular2's Release Candidate 5. Make sure you don't upgrade to this version if you haven't upgraded Angular2 to at least 2.0.0-rc.5

  • Quickstart guide now follows the pattern in Angular 2's Quickstart to add the references to other libs in systemjs.config.js. However if you still want to do it the old way by adding the system bundle, you can still do so, except now its called bundles/angular2-logger.sys.min.js.