web/src/app/services/router.service.ts

import { Injectable } from "@angular/core";
import { Title } from "@angular/platform-browser";
import { ActivatedRoute, NavigationEnd, Router } from "@angular/router";

import { I18nService } from "jslib-common/abstractions/i18n.service";

@Injectable()
export class RouterService {
  private previousUrl: string = undefined;
  private currentUrl: string = undefined;

  constructor(
    private router: Router,
    private activatedRoute: ActivatedRoute,
    private titleService: Title,
    i18nService: I18nService
  ) {
    this.currentUrl = this.router.url;
    router.events.subscribe((event) => {
      if (event instanceof NavigationEnd) {
        this.previousUrl = this.currentUrl;
        this.currentUrl = event.url;

        let title = i18nService.t("pageTitle", "Bitwarden");
        let titleId: string = null;
        let rawTitle: string = null;
        let child = this.activatedRoute.firstChild;
        while (child != null) {
          if (child.firstChild != null) {
            child = child.firstChild;
          } else if (child.snapshot.data != null && child.snapshot.data.title != null) {
            rawTitle = child.snapshot.data.title;
            break;
          } else if (child.snapshot.data != null && child.snapshot.data.titleId != null) {
            titleId = child.snapshot.data.titleId;
            break;
          } else {
            titleId = null;
            rawTitle = null;
            break;
          }
        }

        if (titleId != null || rawTitle != null) {
          const newTitle = rawTitle != null ? rawTitle : i18nService.t(titleId);
          if (newTitle != null && newTitle !== "") {
            title = newTitle + " | " + title;
          }
        }
        this.titleService.setTitle(title);
      }
    });
  }

  getPreviousUrl() {
    return this.previousUrl;
  }

  setPreviousUrl(url: string) {
    this.previousUrl = url;
  }
}