Injecting mock providers only for dev mode


I’ve created a couple of mock classes for testing in the browser. When testing on a device, I manually remove these from the providers list before the build. I now want to automatically include or remove them based on the --prod flag.

I have tried various methods, from webpack config, to environment variables, to custom services. In other parts of the app, I use isDevMode() as a quick getter to change some variables. The trouble is that isDevMode() can’t be called before enableProdMode() which appears to be after the main module is set up.

I would like to conditionally add an array of mock providers to the provider list such as:

const mockProviders = [
    { provide: Camera, useClass: CameraMock },
    { provide: Geolocation, useClass: LocationMock },

    providers: [
    	isDevMode() ? mockProviders : []

Is there a simple way to do this?


I’ve been racking my brain for days to do this cleanly. Tried loads of different examples, and I’ve just managed to solve this, so I’ll post my solution here:

I followed the guide here to set environment variables:

I modified the ENV to have a isDevMode:

export const ENV = {
	mode: 'Production',
	isDevMode: false

Before declaring the app module:

import { ENV } from '@app/env';
let isDev = ENV.isDevMode;

And in my providers:

providers: [
    	isDev ? mockProviders : []

Hope that can help others!

export interface EnvInterface {

  production: boolean;

  firebase: {
    apiKey: string,
    authDomain: string,
    databaseURL: string,
    projectId: string,
    storageBucket: string,
    messagingSenderId: string


export const ENV: EnvInterface = {

  production: false,

  firebase: {


import { ENV } from '@env';

  imports: [
    // ENV.production ? ServiceWorkerModule.register('/ngsw-worker.js') : []
    ServiceWorkerModule.register('/ngsw-worker.js', { enabled: ENV.production }),
      loader: {
        provide: TranslateLoader,
        useFactory: HttpLoaderFactory,
        deps: [ HttpClient ]
  exports: [],
  declarations: [],
  providers: [
    ENV.production ? { provide: ErrorHandler, useClass: BrewErrorHandler } :
      { provide: ErrorHandler, useClass: IonicErrorHandler},
    { provide: LoggerService, useClass: ConsoleLoggerService },
export class CoreModule {
  constructor( @Optional() @SkipSelf() parentModule: CoreModule,
               private translate: TranslateService,
               private afs: AngularFirestore) {

    throwIfAlreadyLoaded(parentModule, 'CoreModule');


    const settings = { timestampsInSnapshots: true };;