Setup ngx-translate and http-loader in app.module.ts

app.module.ts

import { NgModule, ErrorHandler } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { RouteReuseStrategy } from '@angular/router';
import { HttpClientModule, HttpClient } from '@angular/common/http';
import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
import { TranslateHttpLoader } from '@ngx-translate/http-loader';

import { IonicModule, IonicRouteStrategy } from '@ionic/angular';
import { SplashScreen } from '@ionic-native/splash-screen/ngx';
import { StatusBar } from '@ionic-native/status-bar/ngx';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';


export function HttpLoaderFactory(http: HttpClient) {
  return new TranslateHttpLoader(http, "./assets/i18n/", ".json");
}

@NgModule({
  declarations: [AppComponent],
  entryComponents: [],
  imports: [BrowserModule,
    HttpClientModule,
    TranslateModule.forRoot({
      loader: {
        provide: TranslateLoader,
        useFactory: HttpLoaderFactory,
        deps: [HttpClient]
      }
    }),
    IonicModule.forRoot(),
    AppRoutingModule],
  providers: [
    StatusBar,
    SplashScreen,
    { provide: RouteReuseStrategy, useClass: IonicRouteStrategy }
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }