Working lightbox pops up and closes

src/domain/session/SessionViewModel.js

@@ -81,7 +81,12 @@ export class SessionViewModel extends ViewModel {
         }));
         this._updateCreateRoom(createRoom.get());
 
-        setupLightboxNavigation(this, 'lightboxViewModel');
+        setupLightboxNavigation(this, 'lightboxViewModel', (eventId) => {
+            return {
+                room,
+                eventId,
+            };
+        });
 
         const rightpanel = this.navigation.observe("right-panel");
         this.track(rightpanel.subscribe(() => this._updateRightPanel()));

src/domain/session/room/LightboxViewModel.js

@@ -19,11 +19,11 @@ import {ViewModel} from "../../ViewModel";
 export class LightboxViewModel extends ViewModel {
     constructor(options) {
         super(options);
-        this._eventId = options.eventId;
+        this._eventEntry = options.eventEntry;
+        this._eventId = options.eventId || options.eventEntry.id;
         this._unencryptedImageUrl = null;
         this._decryptedImage = null;
         this._closeUrl = this.urlCreator.urlUntilSegment("room");
-        this._eventEntry = options.eventEntry;
         this._date = null;
         this._subscribeToEvent(options.room, options.eventId);
     }

src/domain/session/room/lightbox-navigation.js

@@ -1,31 +1,69 @@
+/*
+Copyright 2022 Bruno Windels <bruno@windels.cloud>
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
 import {LightboxViewModel} from "./LightboxViewModel.js";
 
+// Store the `LightboxViewModel` under a symbol so no one else can tamper with
+// it. This acts like a private field on the class since no one else has the
+// symbol to look it up.
 let lightboxViewModelSymbol = Symbol('lightboxViewModel');
 
-export function updateLightboxViewModel(vm, fieldName, eventId) {
+/**
+ * Destroys and creates a new the `LightboxViewModel` depending if
+ * `lightboxChildOptions.eventEntry` or `lightboxChildOptions.eventId` are
+ * provided.
+ */
+function updateLightboxViewModel(vm, fieldName, lightboxChildOptions) {
+    // Remove any existing `LightboxViewModel` before we assemble the new one below
     if (vm[lightboxViewModelSymbol]) {
         vm[lightboxViewModelSymbol] = vm.disposeTracked(vm[lightboxViewModelSymbol]);
+        // Let the `LightboxView` know that the `LightboxViewModel` has changed
         vm.emitChange(fieldName);
     }
-    if (eventId) {
-        const room = vm._roomFromNavigation();
-        vm[lightboxViewModelSymbol] = vm.track(new LightboxViewModel(vm.childOptions({eventId, room})));
+    // Create the new `LightboxViewModel` if the `eventEntry` exists directly or
+    // `eventId` which we can load from the store 
+    if (lightboxChildOptions.eventId || lightboxChildOptions.eventEntry) {
+        vm[lightboxViewModelSymbol] = vm.track(new LightboxViewModel(vm.childOptions(lightboxChildOptions)));
+        // Let the `LightboxView` know that the `LightboxViewModel` has changed
         vm.emitChange(fieldName);
     }
 }
 
-// Whenever the page navigates somewhere, keep the lightboxViewModel up to date
-export function setupLightboxNavigation(vm, fieldName = 'lightboxViewModel') {
+/**
+ * Handles updating the `LightboxViewModel` whenever the page URL changes and
+ * emits changes which the `LightboxView` will use to re-render. This is a
+ * composable piece of logic to call in an existing `ViewModel`'s constructor.
+ */
+export function setupLightboxNavigation(vm, fieldName = 'lightboxViewModel', lightboxChildOptionsFunction) {
+    // On the given `vm`, create a getter at `fieldName` that the
+    // `LightboxViewModel` is exposed at for usage in the view.
     Object.defineProperty(vm, fieldName, {
         get: function() {
-            vm[lightboxViewModelSymbol];
+            return vm[lightboxViewModelSymbol];
         }
     });
 
+    // Whenever the page navigates somewhere, keep the `lightboxViewModel` up to date
     const lightbox = vm.navigation.observe("lightbox");
     vm.track(lightbox.subscribe(eventId => {
-        updateLightboxViewModel(vm, fieldName, eventId);
+        updateLightboxViewModel(vm, fieldName, lightboxChildOptionsFunction(eventId));
     }));
+    // Also handle the case where the URL already includes `/lightbox/$eventId` (like
+    // from page-load)
     const initialLightBoxEventId = lightbox.get();
-    updateLightboxViewModel(vm, fieldName, initialLightBoxEventId);
+    updateLightboxViewModel(vm, fieldName, lightboxChildOptionsFunction(initialLightBoxEventId));
 }

src/lib.ts

@@ -26,7 +26,7 @@ export {SessionView} from "./platform/web/ui/session/SessionView.js";
 export {RoomViewModel} from "./domain/session/room/RoomViewModel.js";
 export {RoomView} from "./platform/web/ui/session/room/RoomView.js";
 export {LightboxView} from "./platform/web/ui/session/room/LightboxView.js";
-export {setupLightboxNavigation, updateLightboxViewModel} from "./domain/session/room/lightbox-navigation.js";
+export {setupLightboxNavigation} from "./domain/session/room/lightbox-navigation.js";
 export {RightPanelView} from "./platform/web/ui/session/rightpanel/RightPanelView.js";
 export {MediaRepository} from "./matrix/net/MediaRepository";
 export {TilesCollection} from "./domain/session/room/timeline/TilesCollection.js";