Tips for creating a console.log wrapper specifically designed for Angular2 using Typescript

Question

Tips for creating a console.log wrapper specifically designed for Angular2 using Typescript

Is there a way to create a custom global logging function in Angular 2 TypeScript project that can be used instead of console.log for services and components?

I envision the function looking like this:

mylogger.ts

function mylogger(msg){
    console.log(msg);
};

user.service.ts

import 'commons/mylogger';
export class UserService{
  loadUserData(){
    mylogger('About to retrieve data');
    return 'data';
  };
};

javascript typescript angular

Answer 1

Answer №1

If you create this as a service and utilize dependency injection, you can make the class easily accessible to your components.

import {Injectable, provide} from 'angular2/core';

// Customize logging functionality and add methods for different log levels
@Injectable()
export class MyLogger {

  public log(logMsg:string) {
    console.log(logMsg); 
  }
}

export var LOGGING_PROVIDERS:Provider[] = [
      provide(MyLogger, {useClass: MyLogger}),
    ];

To integrate this into your application's top-level injector, include it in the providers array of bootstrap.

import {LOGGING_PROVIDERS} from './mylogger';

bootstrap(App, [LOGGING_PROVIDERS])
  .catch(err => console.error(err));

For a straightforward demonstration, check out this sample: http://plnkr.co/edit/7qnBU2HFAGgGxkULuZCz?p=preview

Answer 2

If you create this as a service and utilize dependency injection, you can make the class easily accessible to your components.

import {Injectable, provide} from 'angular2/core';

// Customize logging functionality and add methods for different log levels
@Injectable()
export class MyLogger {

  public log(logMsg:string) {
    console.log(logMsg); 
  }
}

export var LOGGING_PROVIDERS:Provider[] = [
      provide(MyLogger, {useClass: MyLogger}),
    ];

To integrate this into your application's top-level injector, include it in the providers array of bootstrap.

import {LOGGING_PROVIDERS} from './mylogger';

bootstrap(App, [LOGGING_PROVIDERS])
  .catch(err => console.error(err));

For a straightforward demonstration, check out this sample: http://plnkr.co/edit/7qnBU2HFAGgGxkULuZCz?p=preview

Answer 3

Answer №2

The answer approved exemplifies the concept of printing logs from the logger class, MyLogger, instead of the actual logging class.

To ensure that logs are printed from the precise line calling MyLogger.log(), I have made adjustments to the provided example as shown below:

get debug() {
    return console.debug.bind(console);
}
get log() {
    return console.log.bind(console);
}

I discovered this technique on this page: https://github.com/angular/angular/issues/5458

View the Plunker demo here: http://plnkr.co/edit/0ldN08?p=preview

As stated in Mozilla developer docs,

The bind() method creates a new function that, when called, has its
this keyword set to the provided value, with a given sequence of 
arguments preceding any provided when the new function is called.

For more details on bind, visit:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Answer 4

The answer approved exemplifies the concept of printing logs from the logger class, MyLogger, instead of the actual logging class.

To ensure that logs are printed from the precise line calling MyLogger.log(), I have made adjustments to the provided example as shown below:

get debug() {
    return console.debug.bind(console);
}
get log() {
    return console.log.bind(console);
}

I discovered this technique on this page: https://github.com/angular/angular/issues/5458

View the Plunker demo here: http://plnkr.co/edit/0ldN08?p=preview

As stated in Mozilla developer docs,

The bind() method creates a new function that, when called, has its
this keyword set to the provided value, with a given sequence of 
arguments preceding any provided when the new function is called.

For more details on bind, visit:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Answer 5

Answer №3

To incorporate the 'console.log' function exclusively within your component, follow these steps:

import { Component, OnInit } from '@angular/core';

var output = console.log;

@Component({
  selector: 'app-component',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent implements OnInit {

  constructor() { }

  ngOnInit() { }

  printFunction(term: string): void {
    output('foo');
  }
}

Answer 6

To incorporate the 'console.log' function exclusively within your component, follow these steps:

import { Component, OnInit } from '@angular/core';

var output = console.log;

@Component({
  selector: 'app-component',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent implements OnInit {

  constructor() { }

  ngOnInit() { }

  printFunction(term: string): void {
    output('foo');
  }
}

Answer 7

Answer №4

Have you considered using the console in your main service to customize and conditionally apply console.log?

myComponent.ts

export class myComponent implements OnInit {
 constructor(
        private config: GlobalService
    ) {}

    ngOnInit() {
       this.config.log('func name',{a:'aval'},'three');
    }
}

global.service.ts

@Injectable()
export class GlobalService {

   constructor() { }
   this.prod = true;
   public log(one: any, two?: any, three?: any, four?: any) {
        if (!this.prod) {
             console.log('%c'+one, 'background:red;color:#fff', two, three, four);
        }
    }
}

(Please note that the first parameter must be a string in this example).

Answer 8

Have you considered using the console in your main service to customize and conditionally apply console.log?

myComponent.ts

export class myComponent implements OnInit {
 constructor(
        private config: GlobalService
    ) {}

    ngOnInit() {
       this.config.log('func name',{a:'aval'},'three');
    }
}

global.service.ts

@Injectable()
export class GlobalService {

   constructor() { }
   this.prod = true;
   public log(one: any, two?: any, three?: any, four?: any) {
        if (!this.prod) {
             console.log('%c'+one, 'background:red;color:#fff', two, three, four);
        }
    }
}

(Please note that the first parameter must be a string in this example).

Answer 9

Answer №5

To enable or disable console logging:

logger.service.ts:

import { Injectable } from '@angular/core';

@Injectable()
export class LoggerService {

private oldConsoleLog = null;

enableLogger(){

    if (this.oldConsoleLog == null) { return; }

    window['console']['log'] = this.oldConsoleLog;
}

disableLogger() {
    this.oldConsoleLog = console.log;
    window['console']['log'] = function () { };
};

}

app.component.ts:

@Component({
  selector: 'my-app',
  template: `your templ;ate`
})

export class AppComponent {

constructor(private loggerService: LoggerService) {
    var IS_PRODUCTION = true;

    if ( IS_PRODUCTION ) {
        console.log("LOGGER IS DISABBLED!!!");
        loggerService.disableLogger();
    }

}
}

Answer 10

To enable or disable console logging:

logger.service.ts:

import { Injectable } from '@angular/core';

@Injectable()
export class LoggerService {

private oldConsoleLog = null;

enableLogger(){

    if (this.oldConsoleLog == null) { return; }

    window['console']['log'] = this.oldConsoleLog;
}

disableLogger() {
    this.oldConsoleLog = console.log;
    window['console']['log'] = function () { };
};

}

app.component.ts:

@Component({
  selector: 'my-app',
  template: `your templ;ate`
})

export class AppComponent {

constructor(private loggerService: LoggerService) {
    var IS_PRODUCTION = true;

    if ( IS_PRODUCTION ) {
        console.log("LOGGER IS DISABBLED!!!");
        loggerService.disableLogger();
    }

}
}

Answer 11

Answer №6

I have devised a logger based on the details provided in this section.

It is currently quite basic (and somewhat hacky :-) ), but it does retain the line number information.

@Injectable()
export class LoggerProvider {

constructor() {
  //inject any desired content here
}

public getLogger(name: string) {
  return {

    get log() {
      //Adjust the parameters 
      //An example of colored output
      let msg = '%c[' + name + ']';
      for (let i = 0; i < arguments.length; i++) {
        msg += arguments[i]
      }

      return console.log.bind(console, msg, 'color:blue');
    }

  }
 }
}

I trust that this proves to be useful.

Answer 12

I have devised a logger based on the details provided in this section.

It is currently quite basic (and somewhat hacky :-) ), but it does retain the line number information.

@Injectable()
export class LoggerProvider {

constructor() {
  //inject any desired content here
}

public getLogger(name: string) {
  return {

    get log() {
      //Adjust the parameters 
      //An example of colored output
      let msg = '%c[' + name + ']';
      for (let i = 0; i < arguments.length; i++) {
        msg += arguments[i]
      }

      return console.log.bind(console, msg, 'color:blue');
    }

  }
 }
}

I trust that this proves to be useful.

Answer 13

Answer №7

Implementing a safer(ish) version with Angular 4 and TypeScript 2.3

logger.service.ts

import { InjectionToken } from '@angular/core';

export type LoggerService = Pick<typeof console,
                                 'debug' | 'error' | 'info' | 'log' | 'trace' | 'warn'>;
export const LOGGER_SERVICE = new InjectionToken('LOGGER_SERVICE');
export const ConsoleLoggerServiceProvider = { provide: LOGGER_SERVICE, useValue: console };

my.module.ts

// ...
@NgModule({
  providers: [
    ConsoleLoggerServiceProvider,
    //...
  ],
// ...

my.service.ts

// ...
@Injectable()
export class MyService {

  constructor(@Inject(LOGGER_SERVICE) log: LoggerService) {
//...

Answer 14

Implementing a safer(ish) version with Angular 4 and TypeScript 2.3

logger.service.ts

import { InjectionToken } from '@angular/core';

export type LoggerService = Pick<typeof console,
                                 'debug' | 'error' | 'info' | 'log' | 'trace' | 'warn'>;
export const LOGGER_SERVICE = new InjectionToken('LOGGER_SERVICE');
export const ConsoleLoggerServiceProvider = { provide: LOGGER_SERVICE, useValue: console };

my.module.ts

// ...
@NgModule({
  providers: [
    ConsoleLoggerServiceProvider,
    //...
  ],
// ...

my.service.ts

// ...
@Injectable()
export class MyService {

  constructor(@Inject(LOGGER_SERVICE) log: LoggerService) {
//...

Answer 15

Answer №8

A new logger component for Angular2 has been released on NPM with added support for log levels. Check it out here

Answer 16

A new logger component for Angular2 has been released on NPM with added support for log levels. Check it out here

Tips for creating a console.log wrapper specifically designed for Angular2 using Typescript

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

logger.service.ts

my.module.ts

my.service.ts

Answer №8

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