feat(demo): opportunity to change bs theme by url query (#4870)

Author: Domainv

demo/src/app/common/sidebar/sidebar.component.ts

@@ -1,10 +1,12 @@
+import { ActivatedRoute, NavigationEnd, Router } from '@angular/router';
 import { Component, Inject, OnDestroy, Renderer } from '@angular/core';
-import { NavigationEnd, Router } from '@angular/router';
+import { DOCUMENT } from '@angular/common';
+
 import { isBs3, setTheme } from 'ngx-bootstrap/utils';
 import { routes } from '../../app.routing';
 import { StyleManager } from '../../theme/style-manager';
 import { ThemeStorage } from '../../theme/theme-storage';
-import { DOCUMENT } from '@angular/common';
+
 import { Subscription } from 'rxjs';
 
 const _bs3Css = 'assets/css/bootstrap-3.3.7/css/bootstrap.min.css';
@@ -28,13 +30,15 @@ export class SidebarComponent implements OnDestroy {
   scrollSubscription: Subscription;
 
   constructor(
-    public styleManager: StyleManager,
+    private activatedRoute: ActivatedRoute,
+    private renderer: Renderer,
     private router: Router,
     private themeStorage: ThemeStorage,
-    private renderer: Renderer,
+    public styleManager: StyleManager,
     @Inject(DOCUMENT) private document: any
   ) {
-    const currentTheme = this.themeStorage.getStoredTheme();
+    const themeFromUrl = this.activatedRoute.snapshot.queryParams._bsVersion;
+    const currentTheme = themeFromUrl || this.themeStorage.getStoredTheme();
     if (currentTheme) {
       this.installTheme(currentTheme);
     }