npm install @ngx-translate/core --save

// other module
import {TranslateModule} from '@ngx-translate/core';
@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    // other module
    TranslateModule.forRoot(),

  ],
  providers: [
  ],
  bootstrap: [AppComponent]
})
export class AppModule {
}

npm install @ngx-translate/http-loader --save

// other module
import {TranslateModule} from '@ngx-translate/core';
// 自定義加載方法
export function HttpLoaderFactory(http: HttpClient) {
  return new TranslateHttpLoader(http, './assets/i18n/', '.json?');
}
@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    // other module
    TranslateModule.forRoot({
      loader: {
        provide: TranslateLoader,
        useFactory: HttpLoaderFactory,
        deps: [HttpClient],
      }
    }),
  ],
  providers: [
  ],
  bootstrap: [AppComponent]
})
export class AppModule {
}

// /asserts/il8n/en.json
{
 "Hello": "hello, {{value}}",
 "Introduce": {
  "Name": "my name is {{name}}.",
  "Today": "today is {{date}}, and now time is {{time}}"
 }
}

import { Component } from '@angular/core';
import {TranslateService} from '@ngx-translate/core';
@Component({
 selector: 'app-root',
 templateUrl: './app.component.html',
 styleUrls: ['./app.component.less']
})
export class AppComponent {
 constructor(
   public translate: TranslateService,
 ) {
   this.translate.setDefaultLang('en');
   this.translate.use('en');
 }
}

// app.compent.ts
this.translate.get(
  'Introduce.Name',
  {name: 'Jarvis'}
).subscribe((res: string) => {
  console.log('res', res); // res my name is Jarvis.
});
this.translate.get(
  'Introduce.Today',
  {
    date: new Date().getDate(),
    time: new Date().getTime()
  },
).subscribe((res: string) => {
  console.log('res', res); // res today is 22, and now time is 1534937370461
});

<div>{{'Hello' | translate: param</div>

const param = {
  value: 'world',
};

<span [translate]="'Introduce.Name'" [translateParams]="{name: 'Jarvis'}"></span>

<span translate [translateParams]="{date: '10.11', time: '20:33'}">Introduce.Today</span>

{
 "Hello": "hello, {{value}}",
}

<p [innerHTML]="'Introduce.Name'| translate: param"></p>

instant(key: string|Array<string>), insterpolateParams?: Object):string|Object

this.translate.instant('HELLO', {value: 'Jarvis'});