Initialize app by calling Angular 13 service loader

Question

Initialize app by calling Angular 13 service loader

I'm currently using Angular 13 and attempting to connect with Angular's bootstrapping phase through the APP_INITIALIZER token. I need to create an Angular service that manages the retrieval of our remote configuration. However, I've run into an issue where promises are no longer supported and have been deprecated. Can someone provide guidance on how to refactor the loadAppConfig() method since APP_INITIALIZER only works with promises? Any assistance would be greatly appreciated.

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Injectable()
export class AppConfigService {
  private appConfig;

  constructor(private http: HttpClient) { }

  loadAppConfig() {
    return this.http.get('/assets/data/appConfig.json')
      .toPromise()
      .then(data => {
        this.appConfig = data;
      });
  }

  getConfig() {
    return this.appConfig;
  }
}

angular typescript

Answer 1

Answer №1

When it comes to handling promises and observables, the APP_INITIALIZER in Angular is a versatile tool. According to the documentation provided at https://angular.io/api/core/APP_INITIALIZER,

"If any of these functions returns a Promise or an Observable,"

An example demonstrating the use of an observable can be seen below:

function initializeAppFactory(httpClient: HttpClient): () => Observable<any> {
 return () => httpClient.get("https://someUrl.com/api/user")
   .pipe(
      tap(user => { ... })
   );
}

@NgModule({
  imports: [BrowserModule, HttpClientModule],
  declarations: [AppComponent],
  bootstrap: [AppComponent],
  providers: [{
    provide: APP_INITIALIZER,
    useFactory: initializeAppFactory,
    deps: [HttpClient],
    multi: true
  }]
})
export class AppModule {}

Answer 2

When it comes to handling promises and observables, the APP_INITIALIZER in Angular is a versatile tool. According to the documentation provided at https://angular.io/api/core/APP_INITIALIZER,

"If any of these functions returns a Promise or an Observable,"

An example demonstrating the use of an observable can be seen below:

function initializeAppFactory(httpClient: HttpClient): () => Observable<any> {
 return () => httpClient.get("https://someUrl.com/api/user")
   .pipe(
      tap(user => { ... })
   );
}

@NgModule({
  imports: [BrowserModule, HttpClientModule],
  declarations: [AppComponent],
  bootstrap: [AppComponent],
  providers: [{
    provide: APP_INITIALIZER,
    useFactory: initializeAppFactory,
    deps: [HttpClient],
    multi: true
  }]
})
export class AppModule {}

Initialize app by calling Angular 13 service loader

Answer №1

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