You provided 'undefined' where a stream was expected

Hi!,

I’m trying to use the HttpLoader in an angular 8 project, I’ve followed all the steps in the guide and in this tutorial and i get allways the same error at the chrome console:

“ERROR TypeError: You provided ‘undefined’ where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.”

I think i’m using the correct version (11+ core and 4+ loader) for Angular 8, anyway here are my dependencies form package.josn:

  "dependencies": {
    "@angular/animations": "~8.2.0",
    "@angular/cdk": "~7.3.7",
    "@angular/common": "~8.2.0",
    "@angular/compiler": "~8.2.0",
    "@angular/core": "~8.2.0",
    "@angular/flex-layout": "^7.0.0-beta.24",
    "@angular/forms": "~8.2.0",
    "@angular/material": "^7.3.7",
    "@angular/material-moment-adapter": "^7.3.7",
    "@angular/platform-browser": "~8.2.0",
    "@angular/platform-browser-dynamic": "~8.2.0",
    "@angular/router": "~8.2.0",
    "@fortawesome/fontawesome-free": "^5.9.0",
    "@ng-bootstrap/ng-bootstrap": "^5.1.0",
    "@ngx-translate/core": "^11.0.1",
    "@ngx-translate/http-loader": "^4.0.0",
    "angular-bootstrap-md": "^8.0.0",
    "animate.css": "^3.7.2",
    "chart.js": "^2.8.0",
    "core-js": "^2.5.4",
    "hammerjs": "^2.0.8",
    "moment": "^2.24.0",
    "ngx-device-detector": "^1.3.6",
    "ngx-malihu-scrollbar": "^8.0.0",
    "ngx-skeleton-loader": "^1.2.2",
    "rxjs": "~6.5.2",
    "tslib": "^1.9.0",
    "zone.js": "~0.9.1"
  }

And my app.module.ts:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule, LOCALE_ID } from '@angular/core';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { LoginModule } from './login/login.module';
import { HttpClientModule, HttpClient } from '@angular/common/http';
import { IntranetModule } from './intranet/intranet.module';
import { AlmacenModule } from './intranet/almacen/almacen.module';
import { httpInterceptorProviders } from '../core/interceptors/index';
import { NgxSkeletonLoaderModule } from 'ngx-skeleton-loader';
import localeEs from '@angular/common/locales/es';
import localePt from '@angular/common/locales/pt';
import { registerLocaleData } from '@angular/common';
import {TranslateModule, TranslateLoader} from '@ngx-translate/core';
import {TranslateHttpLoader} from '@ngx-translate/http-loader';


registerLocaleData(localeEs, 'es-ES');
registerLocaleData(localePt, 'pt-PT');

// AoT requires an exported function for factories
export function HttpLoaderFactory(http: HttpClient) {
  return new TranslateHttpLoader(http);
}
@NgModule({
  declarations: [AppComponent],
  imports: [
    BrowserModule,
    BrowserAnimationsModule,
    AppRoutingModule,
    LoginModule,
    NgxSkeletonLoaderModule,
    IntranetModule,
    AlmacenModule,
    HttpClientModule,
    TranslateModule.forRoot({
      loader: {
          provide: TranslateLoader,
          useFactory: HttpLoaderFactory,
          deps: [HttpClient]
      }
  })
  ],
  providers: [
    httpInterceptorProviders,
    { provide: LOCALE_ID, useValue: 'es-ES' },
    // { provide: LOCALE_ID, useValue: 'pt-PT' }
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

I’ve searched in the issues, even google, but I’ve not found anything to solve my problem.

Thank you.

[nschmit]

I got the same error in my angular application (and #921 did not solve it). In my case, the error was in my http-interceptor. I did some error-handling in catchError(…), and accidentally returned undefined in some cases.

@Injectable()
export class HttpErrorInterceptor implements HttpInterceptor {
  intercept(
    request: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {
    const timestamp = Date.now();
    return next.handle(request).pipe(
      timeout(HTTP_TIMEOUT_MS),
      retry(1),
      catchError((error: any) => {
          // pseude code ->
          if (error instanceOf SomeError) {
              return throwError(error);
          }
         // for errors that are not instanceOf SomeError
         // undefined was returned!!!
      })
    );
  }
}

[jnavarrovera]

I’ve been investigating and I found that if I remove my interceptor, it works. I have others applications with both, interceptors and ngx-translate, and they works, the only diference is angular version (7 working, 8 not working)

Someone has any clue?

Thanks!