Add missing childOption

Changes to go along with https://github.com/matrix-org/matrix-public-archive/pull/12

Split out from https://github.com/vector-im/hydrogen-web/pull/653

src/domain/ViewModel.ts

@@ -28,12 +28,14 @@ import type {Clock} from "../platform/web/dom/Clock";
 import type {ILogger} from "../logging/types";
 import type {Navigation} from "./navigation/Navigation";
 import type {URLRouter} from "./navigation/URLRouter";
+import type {History} from "../platform/web/dom/History";
 
 export type Options = {
     platform: Platform
     logger: ILogger
     urlCreator: URLRouter
     navigation: Navigation
+    history: History
     emitChange?: (params: any) => void
 }
 
@@ -142,4 +144,8 @@ export class ViewModel<O extends Options = Options> extends EventEmitter<{change
     get navigation(): Navigation {
         return this._options.navigation;
     }
+
+    get history(): History {
+        return this._options.history;
+    }
 }

src/domain/session/SessionViewModel.js

@@ -20,7 +20,7 @@ import {RoomViewModel} from "./room/RoomViewModel.js";
 import {UnknownRoomViewModel} from "./room/UnknownRoomViewModel.js";
 import {InviteViewModel} from "./room/InviteViewModel.js";
 import {RoomBeingCreatedViewModel} from "./room/RoomBeingCreatedViewModel.js";
-import {LightboxViewModel} from "./room/LightboxViewModel.js";
+import {setupLightboxNavigation} from "./room/lightbox-navigation.js";
 import {SessionStatusViewModel} from "./SessionStatusViewModel.js";
 import {RoomGridViewModel} from "./RoomGridViewModel.js";
 import {SettingsViewModel} from "./settings/SettingsViewModel.js";
@@ -81,12 +81,12 @@ export class SessionViewModel extends ViewModel {
         }));
         this._updateCreateRoom(createRoom.get());
 
-        const lightbox = this.navigation.observe("lightbox");
-        this.track(lightbox.subscribe(eventId => {
-            this._updateLightbox(eventId);
-        }));
-        this._updateLightbox(lightbox.get());
-
+        setupLightboxNavigation(this, 'lightboxViewModel', (eventId) => {
+            return {
+                room: this._roomFromNavigation(),
+                eventId,
+            };
+        });
 
         const rightpanel = this.navigation.observe("right-panel");
         this.track(rightpanel.subscribe(() => this._updateRightPanel()));
@@ -267,21 +267,6 @@ export class SessionViewModel extends ViewModel {
         this.emitChange("activeMiddleViewModel");
     }
 
-    _updateLightbox(eventId) {
-        if (this._lightboxViewModel) {
-            this._lightboxViewModel = this.disposeTracked(this._lightboxViewModel);
-        }
-        if (eventId) {
-            const room = this._roomFromNavigation();
-            this._lightboxViewModel = this.track(new LightboxViewModel(this.childOptions({eventId, room})));
-        }
-        this.emitChange("lightboxViewModel");
-    }
-
-    get lightboxViewModel() {
-        return this._lightboxViewModel;
-    }
-
     _roomFromNavigation() {
         const roomId = this.navigation.path.get("room")?.value;
         const room = this._client.session.rooms.get(roomId);

src/domain/session/room/LightboxViewModel.js

@@ -19,21 +19,25 @@ 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 = null;
         this._date = null;
         this._subscribeToEvent(options.room, options.eventId);
     }
 
     _subscribeToEvent(room, eventId) {
-        const eventObservable = room.observeEvent(eventId);
-        this.track(eventObservable.subscribe(eventEntry => {
-            this._loadEvent(room, eventEntry);
-        }));
-        this._loadEvent(room, eventObservable.get());
+        let event = this._eventEntry;
+        if (!this._eventEntry) {
+            const eventObservable = room.observeEvent(eventId);
+            this.track(eventObservable.subscribe(eventEntry => {
+                this._loadEvent(room, eventEntry);
+            }));
+            event = eventObservable.get();
+        }
+        this._loadEvent(room, event);
     }
 
     async _loadEvent(room, eventEntry) {
@@ -92,6 +96,6 @@ export class LightboxViewModel extends ViewModel {
     }
 
     close() {
-        this.platform.history.pushUrl(this.closeUrl);
+        this.history.pushUrl(this.closeUrl);
     }
 }

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

@@ -0,0 +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');
+
+/**
+ * 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);
+    }
+    // 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);
+    }
+}
+
+/**
+ * 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() {
+            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, lightboxChildOptionsFunction(eventId));
+    }));
+    // Also handle the case where the URL already includes `/lightbox/$eventId` (like
+    // from page-load)
+    const initialLightBoxEventId = lightbox.get();
+    updateLightboxViewModel(vm, fieldName, lightboxChildOptionsFunction(initialLightBoxEventId));
+}

src/lib.ts

@@ -25,6 +25,8 @@ export {SessionViewModel} from "./domain/session/SessionViewModel.js";
 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} from "./domain/session/room/lightbox-navigation.js";
 export {TimelineViewModel} from "./domain/session/room/timeline/TimelineViewModel.js";
 export {tileClassForEntry} from "./domain/session/room/timeline/tiles/index";
 export type {TimelineEntry, TileClassForEntryFn, Options, TileConstructor} from "./domain/session/room/timeline/tiles/index";
@@ -62,6 +64,7 @@ export {TextMessageView} from "./platform/web/ui/session/room/timeline/TextMessa
 export {VideoView} from "./platform/web/ui/session/room/timeline/VideoView.js";
 
 export {Navigation} from "./domain/navigation/Navigation.js";
+export {History} from "./platform/web/dom/History.js";
 export {ComposerViewModel} from "./domain/session/room/ComposerViewModel.js";
 export {MessageComposer} from "./platform/web/ui/session/room/MessageComposer.js";
 export {TemplateView} from "./platform/web/ui/general/TemplateView";

src/platform/web/dom/History.js

@@ -30,10 +30,10 @@ export class History extends BaseObservableValue {
         But for SSO, we need to handle <root>/?loginToken=<TOKEN>
         Handle that as a special case for now.
         */
-        if (document.location.search.includes("loginToken")) {
+        if (document?.location?.search.includes("loginToken")) {
             return document.location.search;
         }
-        return document.location.hash;
+        return document?.location?.hash;
     }
 
     /** does not emit */

src/platform/web/main.js

@@ -43,6 +43,7 @@ export async function main(platform) {
             // so we call it that in the view models
             urlCreator: urlRouter,
             navigation,
+            history: platform.history,
         });
         await vm.load();
         platform.createAndMountRootView(vm);