// 1. 在模板中使用i18n标记
<h1 i18n="Site header|An introduction header for this sample@@introductionHeader">
  Hello i18n!
</h1>

// 2. 提取翻译文件
ng xi18n --output-path src/locale

// 3. 为每种语言创建翻译文件（如messages.fr.xlf）

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

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

export function HttpLoaderFactory(http: HttpClient) {
  return new TranslateHttpLoader(http);
}

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

// 1. 创建翻译文件（如assets/i18n/en.json）
{
  "HELLO": "Hello",
  "WELCOME": "Welcome {{name}}"
}

// 2. 在组件中使用
import { TranslateService } from '@ngx-translate/core';

constructor(private translate: TranslateService) {
  // 设置默认语言
  translate.setDefaultLang('en');
}

// 切换语言
switchLanguage(language: string) {
  this.translate.use(language);
}

<!-- 在模板中使用 -->
<h1>{{ 'HELLO' | translate }}</h1>
<p>{{ 'WELCOME' | translate:param }}</p>

// translation.service.ts
import { Injectable } from '@angular/core';

@Injectable()
export class TranslationService {
  private currentLang = 'en';
  private translations = {
    en: {
      HELLO: 'Hello',
      WELCOME: 'Welcome {{name}}'
    },
    fr: {
      HELLO: 'Bonjour',
      WELCOME: 'Bienvenue {{name}}'
    }
  };

  setLanguage(lang: string) {
    this.currentLang = lang;
  }

  getTranslation(key: string, params?: any): string {
    let translation = this.translations[this.currentLang][key] || key;
    
    if (params) {
      Object.keys(params).forEach(param => {
        translation = translation.replace(`{{${param}}}`, params[param]);
      });
    }
    
    return translation;
  }
}