Adding the internationalization (i18n) component to an Angular application

Introduction

Angular is a development platform for building web, mobile, and desktop applications using HTML, CSS, and TypeScript (JavaScript). Currently, Angular is at version 14 and Google is the main maintainer of the project.

@ngx-translate is an internationalization (i18n) component library with many configuration options.

Prerequisites

Before you start, you need to install and configure the tools:

• git
• Node.js and npm
• Angular CLI
• IDE (e.g. Visual Studio Code)

Getting started

Create the Angular application

1. Let’s create the application with the Angular base structure using the @angular/cli with the route file and the SCSS style format.

ng new angular-internationalization
? Would you like to add Angular routing? Yes
? Which stylesheet format would you like to use? SCSS   [ https://sass-lang.com/documentation/syntax#scss                ]
CREATE angular-internationalization/README.md (1073 bytes)
CREATE angular-internationalization/.editorconfig (274 bytes)
CREATE angular-internationalization/.gitignore (604 bytes)
CREATE angular-internationalization/angular.json (3339 bytes)
CREATE angular-internationalization/package.json (1090 bytes)
CREATE angular-internationalization/tsconfig.json (783 bytes)
CREATE angular-internationalization/.browserslistrc (703 bytes)
CREATE angular-internationalization/karma.conf.js (1445 bytes)
CREATE angular-internationalization/tsconfig.app.json (287 bytes)
CREATE angular-internationalization/tsconfig.spec.json (333 bytes)
CREATE angular-internationalization/src/favicon.ico (948 bytes)
CREATE angular-internationalization/src/index.html (313 bytes)
CREATE angular-internationalization/src/main.ts (372 bytes)
CREATE angular-internationalization/src/polyfills.ts (2820 bytes)
CREATE angular-internationalization/src/styles.scss (80 bytes)
CREATE angular-internationalization/src/test.ts (788 bytes)
CREATE angular-internationalization/src/assets/.gitkeep (0 bytes)
CREATE angular-internationalization/src/environments/environment.prod.ts (51 bytes)
CREATE angular-internationalization/src/environments/environment.ts (658 bytes)
CREATE angular-internationalization/src/app/app-routing.module.ts (245 bytes)
CREATE angular-internationalization/src/app/app.module.ts (393 bytes)
CREATE angular-internationalization/src/app/app.component.scss (0 bytes)
CREATE angular-internationalization/src/app/app.component.html (24617 bytes)
CREATE angular-internationalization/src/app/app.component.spec.ts (1139 bytes)
CREATE angular-internationalization/src/app/app.component.ts (233 bytes)
✔ Packages installed successfully.

2. Install and configure the Bootstrap CSS framework. Do steps 2 and 3 of the post Adding the Bootstrap CSS framework to an Angular application.

3. Install the @ngx-translate/core and @ngx-translate/http-loader libraries.

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

4. Import the HttpClient, HttpClientModule, TranslateModule, TranslateLoader and TranslateHttpLoader modules. Change the app.module.ts file and add the lines as below.

import { HttpClient, HttpClientModule } from '@angular/common/http';
import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
import { TranslateHttpLoader } from '@ngx-translate/http-loader';

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

imports: [
  BrowserModule,
  HttpClientModule,
  TranslateModule.forRoot({
    loader: {
      provide: TranslateLoader,
      useFactory: (createTranslateLoader),
      deps: [HttpClient],
    },
    defaultLanguage: 'en-US',
  }),
  AppRoutingModule,
],

5. Create the de-DE.json, en-US.json es-ES.json, fr-FR.json and pt-BR.json files in the src/assets/i18n folder.

6. Add the content below in the de-DE.json file.

{
  "hello": "Hallo, {{name}}!"
}

7. Add the content below in the en-US.json file.

{
  "hello": "Hello, {{name}}!"
}

8. Add the content below in the es-ES.json file.

{
  "hello": "Hola, {{name}}!"
}

9. Add the content below in the fr-FR.json file.

{
  "hello": "Bonjour, {{name}}!"
}

10. Add the content below in the pt-BR.json file.

{
  "hello": "Olá, {{name}}!"
}

11. Remove the contents of the AppComponent class from the src/app/app.component.ts file. Import the TranslateService service and create the changeLanguage method as below.

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

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

  constructor(public translateService: TranslateService) {
  }

  public changeLanguage(language: string): void {
    this.translateService.use(language);
  }

}

12. Remove the contents of the src/app/app.component.html file. Add the buttons as below.

<div class="container-fluid py-3">
  <h1>Angular Internationalization (i18n)</h1>

  <div class="btn-group btn-group-sm py-5">
    <button type="button" class="btn btn-sm btn-outline-secondary" (click)="changeLanguage('en-US')" [class.active]="translateService.currentLang !== 'pt-BR'">English</button>
    <button type="button" class="btn btn-sm btn-outline-secondary" (click)="changeLanguage('pt-BR')" [class.active]="translateService.currentLang === 'pt-BR'">Português</button>
  </div>

  <h3>{{ "hello" | translate: { name: "Angular" } }}</h3>
</div>

13. Run the application with the command below.

npm start

> [email protected] start
> ng serve

✔ Browser application bundle generation complete.

Initial Chunk Files | Names         |      Size
vendor.js           | vendor        |   2.57 MB
styles.css          | styles        | 266.58 kB
polyfills.js        | polyfills     | 128.54 kB
scripts.js          | scripts       |  76.67 kB
main.js             | main          |  13.03 kB
runtime.js          | runtime       |   6.66 kB

                    | Initial Total |   3.05 MB

Build at: 2021-08-15T20:12:53.818Z - Hash: 9462fdcfd1de35681ab4 - Time: 11933ms

** Angular Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/ **


✔ Compiled successfully.

14. Ready! Access the URL http://localhost:4200/ and check if the application is working. See the application working on GitHub Pages and Stackblitz.

The application repository is available at https://github.com/rodrigokamada/angular-internationalization.

This tutorial was posted on my blog in portuguese.