ng-log-service

Angular 5 Logging Service. Log listeners listen to log events and are notified when they occur.

Installation

npm install --save ng-log-service

Full Documentation

View Complete Documentation

Example Usage

1. Create a Class that Implements ILogListener

	
import { Injectable } from '@angular/core';
import { ILogListener, ALL, LogLevel, ILogMessage } from 'ng-log-service';

@Injectable()
export class MyCustomListener implements ILogListener {
    
    namespace = ALL; // what namespace you want to listen for
    level = LogLevel.All; // log level

    onLog(namespace: string, level: LogLevel, logMessage: ILogMessage) {
        // do what you want here
        console.log(namespace, level, logMessage);
    }

    onGroupCommand(namespace: string, type: GroupCommand, label?: string): void {
        // render appropriate group statement
        switch (type) {
            case GroupCommand.GroupStart:
                console.group(label);
                break;
            case GroupCommand.GroupCollapsed:
                console.groupCollapsed(label);
                break;
            case GroupCommand.GroupEnd:
                console.groupEnd();
        }
    }

}

2. Register Your Listener(s) in your App Root Module

import { LogModule, ConsoleListener, ExtensionListener, LOG_LISTENER, ConsoleListenerConfig } from 'ng-log-service';

// Import Your Log Listeners you want to register
import { MyCustomListener } from './listeners/my-custom-listener';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    LogModule
  ],
  providers: [
    ConsoleListenerConfig,
    { provide: LOG_LISTENER, useClass: ConsoleListener, multi: true, deps: [ConsoleListenerConfig] },
  	{ provide: LOG_LISTENER, useClass: ExtensionListener, multi: true },
    { provide: LOG_LISTENER, useClass: MyCustomListener, multi: true },
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

3. Use the Log Service

import { LogService, LogLevel, ILogMessage } from 'ng-log-service';

@Component({
  selector: 'app-landing-page',
  templateUrl: './landing-page.html',
  styleUrls: ['./landing-page.scss'],
  providers: [LogService] // Inject the LogService
})
export class LandingPage implements OnInit {
  
  constructor(private logService: LogService) {}

    ngOnInit() {
        
        // specify a namespace for the logs
    	this.logService.namespace = 'LandingPage'; 
    	
    	// All of these methods support passing in any object as a second parameter
    	this.logService.log('Landing page log', { data: 'optional' });
        this.logService.info('Landing page info');
        this.logService.debug('Landing page debug');
        this.logService.warn('Landing page warn');
        this.logService.error('Landing page error');
    	this.logService.fatal('Landing page fatal error');
    
    	// Deferred execution of your log. Will not execute unless a listener is subscribed.
    	// If you need to do any 'heavy lifting' before logging a message, use logDeferred.
    	// This will only execute if there is at least on subscriber.
    	this.logService.logDeferred(LogLevel.Warn, (): ILogMessage => {
    		// do some work
    		// must return an ILogMessage object
    		return {
    			message: 'hello world!'+this.translate.currentLang,
    			obj: {dummy: 'data'}
    		};
        });

    }
}

Every time you log with the logService, it will find any registered subscribers and notify them by calling the onLog method.

Licensing

This software is licensed with the MIT license.