dspace-angular/src/app/shared/lang-switch/lang-switch.component.ts

import { Component, OnInit, ElementRef } from '@angular/core';
import { TranslateService } from '@ngx-translate/core';
import { LangConfig } from '../../../config/lang-config.interface';
import { environment } from '../../../environments/environment';
import { LocaleService } from '../../core/locale/locale.service';

@Component({
  selector: 'ds-lang-switch',
  styleUrls: ['lang-switch.component.scss'],
  templateUrl: 'lang-switch.component.html',
})

/**
 * Component representing a switch for changing the interface language throughout the application
 * If only one language is active, the component will disappear as there are no languages to switch to.
 */
export class LangSwitchComponent implements OnInit {

  // All of the languages that are active, meaning that a user can switch between them.
  activeLangs: LangConfig[];

  // A language switch only makes sense if there is more than one active language to switch between.
  moreThanOneLanguage: boolean;

  constructor(
    public el: ElementRef,
    public translate: TranslateService,
    private localeService: LocaleService
  ) {
  }

  ngOnInit(): void {
    this.activeLangs = environment.languages.filter((MyLangConfig) => MyLangConfig.active === true);
    this.moreThanOneLanguage = (this.activeLangs.length > 1);
    if (!this.moreThanOneLanguage) {
      this.el.nativeElement.style.display = 'none';
    }
  }

  /**
   * Returns the label for the current language
   */
  currentLangLabel(): string {
    return this.activeLangs.find((MyLangConfig) => MyLangConfig.code === this.translate.currentLang).label;
  }

  /**
   * Returns the label for a specific language code
   */
  langLabel(langcode: string): string {
    return this.activeLangs.find((MyLangConfig) => MyLangConfig.code === langcode).label;
  }

  /**
   * Switch to a language and store it in a cookie
   * @param lang    The language to switch to
   */
  useLang(lang: string) {
    this.localeService.setCurrentLanguageCode(lang);
    this.localeService.refreshAfterChangeLanguage();
  }

}