app.module.ts

// omitted imports for brevity

@NgModule({
  declarations: [
    // declarations imports for brevity
  ],
  imports: [
    // omitted imports for brevity
  ],
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: AuthInterceptor,
      multi: true
    },
    // omitted rest of providers for brevity
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }