How to use i18next to translate with Angular plugin?

1. Installing Dependencies

First, install i18next and the Angular translation plugin in your Angular project using the following npm command:

bash
npm install i18next @ngx-translate/core --save

2. Configuring i18next

Next, configure i18next in your Angular project. This is typically implemented within a core module such as AppModule. Import the i18next module and set up necessary configurations, including the default language and fallback language.

typescript
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { HttpClientModule, HttpClient } from '@angular/common/http';
import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
import { TranslateHttpLoader } from '@ngx-translate/http-loader';
import { i18nextInit } from 'some-i18next-init-function';

// i18next initialization
i18nextInit();

// AOT compilation requires an exported function for factories
export function HttpLoaderFactory(http: HttpClient) {
    return new TranslateHttpLoader(http);
}

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

3. Loading Language Files

i18next relies on language files for translations. Create these files and store them in the appropriate directory, typically assets/i18n/ within your project. For example, for English and Chinese, you would have en.json and zh.json files.

json
// en.json
{
    "HELLO": "Hello"
}

// zh.json
{
    "HELLO": "你好"
}

4. Using Translation

Within your Angular components, utilize the TranslateService from ngx-translate for translations. Inject this service into the component's constructor and use it to fetch translated strings.

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

@Component({
    selector: 'app-root',
    template: `<h1>{{ 'HELLO' | translate }}</h1>`
})
export class AppComponent {
    constructor(private translate: TranslateService) {
        translate.setDefaultLang('en');
        translate.use('en');
    }
}

5. Switching Languages

Switch the application language easily by invoking the use() method of TranslateService with the relevant language code.

typescript
switchLanguage(language: string) {
    this.translate.use(language);
}

Summary

By following these steps, you can implement multilingual support in your Angular project using i18next and the ngx-translate plugin. Properly configure and load language files, then leverage the TranslateService in your components for dynamic translations. This will significantly enhance your application's internationalization and user experience.