improve race condition for opening lightbox

src/frontend/app/ui/gallery/filter/filter.service.ts

@@ -2,7 +2,7 @@ import {Injectable} from '@angular/core';
 import {BehaviorSubject, Observable} from 'rxjs';
 import {PhotoDTO} from '../../../../../common/entities/PhotoDTO';
 import {DirectoryContent} from '../contentLoader.service';
-import {map, switchMap} from 'rxjs/operators';
+import {debounceTime, map, switchMap} from 'rxjs/operators';
 
 export enum FilterRenderType {
   enum = 1,
@@ -224,6 +224,7 @@ export class FilterService {
     directoryContent: Observable<DirectoryContent>
   ): Observable<DirectoryContent> {
     return directoryContent.pipe(
+      debounceTime(1),
       switchMap((dirContent: DirectoryContent) => {
         this.statistic = this.getStatistic(dirContent);
         this.resetFilters(false);

src/frontend/app/ui/gallery/grid/grid.gallery.component.ts

@@ -385,6 +385,9 @@ export class GalleryGridComponent
    * Makes sure that the photo with the given mediaString is visible on the screen
    */
   private renderUpToMedia(mediaStringId: string): void {
+    if (!this.mediaGroups) {
+      return;
+    }
     let groupIndex = -1;
     let mediaIndex = -1;
     for (let i = 0; i < this.mediaGroups.length; ++i) {

src/frontend/app/ui/gallery/lightbox/lightbox.gallery.component.ts

@@ -105,11 +105,12 @@ export class GalleryLightboxComponent implements OnDestroy, OnInit {
     this.updatePhotoFrameDim();
     this.subscription.route = this.route.queryParams.subscribe(
       (params: Params) => {
+        this.delayedMediaShow = null;
         if (
           params[QueryParams.gallery.photo] &&
           params[QueryParams.gallery.photo] !== ''
         ) {
-            this.delayedMediaShow = params[QueryParams.gallery.photo]
+          this.delayedMediaShow = params[QueryParams.gallery.photo];
           // photos are not yet available to show
           if (!this.gridPhotoQL) {
             return;