Getting started with translation in Angular 5 with ngx-translate

Introduction

Ngx-translate is an internationalization (i18n) library for Angular.

Let’s see how it works in an Angular 5 project with Visual Studio code

Step 1

Download following packages:

Core package

npm install @ngx-translate/core@^9.1.1 -–save

It’s important not to use version 10 because it’s only compatible with Angular 6

If you still use the Angular 4 get the latest compatible version (7.2.2).

Http loader package

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

if you’re still on Angular <4.3, please use Http from @angular/http with http-loader@0.1.0

Step 2

Create a httpLoaderFactory that inherits from TranslateHttpLoader

import { HttpClient } from '@angular/common/http';
import { TranslateHttpLoader } from '@ngx-translate/http-loader';

export function httpLoaderFactory(httpClient: HttpClient): TranslateHttpLoader {
   return new TranslateHttpLoader(httpClient, './assets/i18n/', '.json');
}

Assets/i18n will contains json resource file for each language: [lang].json

Step 3

Create languages files:

Example:

{
   "APP" : {
              "TITLE" : "ngx-translate demonstration",
              "BODY" : "It works very well!"
           }
}

Step 4

Setup app.module.ts by importing required modules:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { TranslateLoader, TranslateModule } from '@ngx-translate/core';
import { AppComponent } from './app.component';
import { HttpClientModule, HttpClient } from '@angular/common/http';
import { httpLoaderFactory } from './services/httpLoaderFactory';

@NgModule({
   declarations: [
      AppComponent
   ],
   imports: [
      BrowserModule,
      HttpClientModule,
      TranslateModule.forRoot({
         loader: {
            provide: TranslateLoader,
            useFactory: httpLoaderFactory,
            deps: [HttpClient]
         }
      }),
   ],
   providers: [],
   bootstrap: [AppComponent]
})

export class AppModule { }

Step 5

Set language to use like this in your component:

import { Component } from '@angular/core';
import { TranslateService } from '@ngx-translate/core';

@Component({
   selector:'app-root',
   templateUrl:'./app.component.html',
   styleUrls: ['./app.component.css']
})

export class AppComponent {
   title='app';

   constructor(private_translate:TranslateService) {
      this._translate.setDefaultLang('en');
      this._translate.use('en');
   }
}

SetDefaultLang is used to set a fallback language when a translation isn’t found in the current language. use the lang to use, if the lang isn’t available, it will use the current loader to get them.

Build then a method that can allow to switch to another language.

Step 6

Test your app!

Example:

<div style="text-align:center">
   <h1>
      {{'APP.TITLE' | translate}}
   </h1>
</div>

Result: