use ViewModel super class for all view models that need binding

src/domain/BrawlViewModel.js

@@ -1,9 +1,9 @@
 import {SessionViewModel} from "./session/SessionViewModel.js";
 import {LoginViewModel} from "./LoginViewModel.js";
 import {SessionPickerViewModel} from "./SessionPickerViewModel.js";
-import {EventEmitter} from "../utils/EventEmitter.js";
+import {ViewModel} from "./ViewModel.js";
 
-export class BrawlViewModel extends EventEmitter {
+export class BrawlViewModel extends ViewModel {
     constructor({createSessionContainer, sessionInfoStorage, storageFactory, clock}) {
         super();
         this._createSessionContainer = createSessionContainer;
@@ -32,7 +32,7 @@ export class BrawlViewModel extends EventEmitter {
         if (sessionContainer) {
             this._setSection(() => {
                 this._sessionContainer = sessionContainer;
-                this._sessionViewModel = new SessionViewModel(sessionContainer);
+                this._sessionViewModel = new SessionViewModel(this.childOptions({sessionContainer}));
             });
         } else {
             // switch between picker and login
@@ -96,7 +96,7 @@ export class BrawlViewModel extends EventEmitter {
         }
         // now set it again
         setter();
-        this.emit("change", "activeSection");
+        this.emitChange("activeSection");
     }
 
     get error() { return this._error; }

src/domain/LoginViewModel.js

@@ -1,7 +1,7 @@
-import {EventEmitter} from "../utils/EventEmitter.js";
+import {ViewModel} from "./ViewModel.js";
 import {SessionLoadViewModel} from "./SessionLoadViewModel.js";
 
-export class LoginViewModel extends EventEmitter {
+export class LoginViewModel extends ViewModel {
     constructor({sessionCallback, defaultHomeServer, createSessionContainer}) {
         super();
         this._createSessionContainer = createSessionContainer;
@@ -10,20 +10,6 @@ export class LoginViewModel extends EventEmitter {
         this._loadViewModel = null;
     }
 
-    // TODO: this will need to support binding
-    // if any of the expr is a function, assume the function is a binding, and return a binding function ourselves
-    i18n(parts, ...expr) {
-        // just concat for now
-        let result = "";
-        for (let i = 0; i < parts.length; ++i) {
-            result = result + parts[i];
-            if (i < expr.length) {
-                result = result + expr[i];
-            }
-        }
-        return result;
-    }
-
     get defaultHomeServer() { return this._defaultHomeServer; }
 
     get loadViewModel() {return this._loadViewModel; }
@@ -42,14 +28,14 @@ export class LoginViewModel extends EventEmitter {
                 } else {
                     // show list of session again
                     this._loadViewModel = null;
-                    this.emit("change", "loadViewModel");
+                    this.emitChange("loadViewModel");
                 }
             },
             deleteSessionOnCancel: true,
             homeserver,
         });
         this._loadViewModel.start();
-        this.emit("change", "loadViewModel");
+        this.emitChange("loadViewModel");
     }
 
     cancel() {

src/domain/SessionLoadViewModel.js

@@ -1,8 +1,8 @@
-import {EventEmitter} from "../utils/EventEmitter.js";
 import {LoadStatus, LoginFailure} from "../matrix/SessionContainer.js";
 import {SyncStatus} from "../matrix/Sync.js";
+import {ViewModel} from "./ViewModel.js";
 
-export class SessionLoadViewModel extends EventEmitter {
+export class SessionLoadViewModel extends ViewModel {
     constructor({createAndStartSessionContainer, sessionCallback, homeserver, deleteSessionOnCancel}) {
         super();
         this._createAndStartSessionContainer = createAndStartSessionContainer;
@@ -19,10 +19,10 @@ export class SessionLoadViewModel extends EventEmitter {
         }
         try {
             this._loading = true;
-            this.emit("change");
+            this.emitChange();
             this._sessionContainer = this._createAndStartSessionContainer();
             this._waitHandle = this._sessionContainer.loadStatus.waitFor(s => {
-                this.emit("change");
+                this.emitChange();
                 // wait for initial sync, but not catchup sync
                 const isCatchupSync = s === LoadStatus.FirstSync &&
                     this._sessionContainer.sync.status === SyncStatus.CatchupSync;
@@ -50,7 +50,7 @@ export class SessionLoadViewModel extends EventEmitter {
             this._error = err;
         } finally {
             this._loading = false;
-            this.emit("change");
+            this.emitChange();
         }
     }
 
@@ -72,7 +72,7 @@ export class SessionLoadViewModel extends EventEmitter {
             this._sessionCallback();
         } catch (err) {
             this._error = err;
-            this.emit("change");
+            this.emitChange();
         }
     }
 

src/domain/SessionPickerViewModel.js

@@ -1,8 +1,8 @@
 import {SortedArray} from "../observable/index.js";
-import {EventEmitter} from "../utils/EventEmitter.js";
 import {SessionLoadViewModel} from "./SessionLoadViewModel.js";
+import {ViewModel} from "./ViewModel.js";
 
-class SessionItemViewModel extends EventEmitter {
+class SessionItemViewModel extends ViewModel {
     constructor(sessionInfo, pickerVM) {
         super();
         this._pickerVM = pickerVM;
@@ -19,31 +19,31 @@ class SessionItemViewModel extends EventEmitter {
 
     async delete() {
         this._isDeleting = true;
-        this.emit("change", "isDeleting");
+        this.emitChange("isDeleting");
         try {
             await this._pickerVM.delete(this.id);
         } catch(err) {
             this._error = err;
             console.error(err);
-            this.emit("change", "error");
+            this.emitChange("error");
         } finally {
             this._isDeleting = false;
-            this.emit("change", "isDeleting");
+            this.emitChange("isDeleting");
         }
     }
 
     async clear() {
         this._isClearing = true;
-        this.emit("change");
+        this.emitChange();
         try {
             await this._pickerVM.clear(this.id);
         } catch(err) {
             this._error = err;
             console.error(err);
-            this.emit("change", "error");
+            this.emitChange("error");
         } finally {
             this._isClearing = false;
-            this.emit("change", "isClearing");
+            this.emitChange("isClearing");
         }
     }
 
@@ -82,7 +82,7 @@ class SessionItemViewModel extends EventEmitter {
             const json = JSON.stringify(data, undefined, 2);
             const blob = new Blob([json], {type: "application/json"});
             this._exportDataUrl = URL.createObjectURL(blob);
-            this.emit("change", "exportDataUrl");
+            this.emitChange("exportDataUrl");
         } catch (err) {
             alert(err.message);
             console.error(err);
@@ -93,13 +93,13 @@ class SessionItemViewModel extends EventEmitter {
         if (this._exportDataUrl) {
             URL.revokeObjectURL(this._exportDataUrl);
             this._exportDataUrl = null;
-            this.emit("change", "exportDataUrl");
+            this.emitChange("exportDataUrl");
         }
     }
 }
 
 
-export class SessionPickerViewModel extends EventEmitter {
+export class SessionPickerViewModel extends ViewModel {
     constructor({storageFactory, sessionInfoStorage, sessionCallback, createSessionContainer}) {
         super();
         this._storageFactory = storageFactory;
@@ -141,12 +141,12 @@ export class SessionPickerViewModel extends EventEmitter {
                     } else {
                         // show list of session again
                         this._loadViewModel = null;
-                        this.emit("change", "loadViewModel");
+                        this.emitChange("loadViewModel");
                     }
                 }
             });
             this._loadViewModel.start();
-            this.emit("change", "loadViewModel");
+            this.emitChange("loadViewModel");
         }
     }
 

src/domain/ViewModel.js

@@ -2,10 +2,13 @@
 // as in some cases it would really be more convenient to have multiple events (like telling the timeline to scroll down)
 // we do need to return a disposable from EventEmitter.on, or at least have a method here to easily track a subscription to an EventEmitter
 
-export class ViewModel extends ObservableValue {
+import {EventEmitter} from "../utils/EventEmitter.js";
+import {Disposables} from "../utils/Disposables.js";
+
+export class ViewModel extends EventEmitter {
     constructor(options) {
         super();
-        this.disposables = new Disposables();
+        this.disposables = null;
         this._options = options;
     }
 
@@ -14,10 +17,33 @@ export class ViewModel extends ObservableValue {
     }
 
     track(disposable) {
+        if (!this.disposables) {
+            this.disposables = new Disposables();
+        }
         this.disposables.track(disposable);
     }
 
     dispose() {
-        this.disposables.dispose();
+        if (this.disposables) {
+            this.disposables.dispose();
+        }
+    }
+
+    // TODO: this will need to support binding
+    // if any of the expr is a function, assume the function is a binding, and return a binding function ourselves
+    i18n(parts, ...expr) {
+        // just concat for now
+        let result = "";
+        for (let i = 0; i < parts.length; ++i) {
+            result = result + parts[i];
+            if (i < expr.length) {
+                result = result + expr[i];
+            }
+        }
+        return result;
+    }
+
+    emitChange(changedProps) {
+        this.emit("change", changedProps);
     }
 }

src/domain/session/SessionViewModel.js

@@ -1,13 +1,14 @@
-import {EventEmitter} from "../../utils/EventEmitter.js";
 import {RoomTileViewModel} from "./roomlist/RoomTileViewModel.js";
 import {RoomViewModel} from "./room/RoomViewModel.js";
 import {SyncStatusViewModel} from "./SyncStatusViewModel.js";
+import {ViewModel} from "../ViewModel.js";
 
-export class SessionViewModel extends EventEmitter {
+export class SessionViewModel extends ViewModel {
-    constructor(sessionContainer) {
+    constructor(options) {
-        super();
+        super(options);
+        const sessionContainer = options.sessionContainer;
         this._session = sessionContainer.session;
-        this._syncStatusViewModel = new SyncStatusViewModel(sessionContainer.sync);
+        this._syncStatusViewModel = new SyncStatusViewModel(this.childOptions(sessionContainer.sync));
         this._currentRoomViewModel = null;
         const roomTileVMs = this._session.rooms.mapValues((room, emitUpdate) => {
             return new RoomTileViewModel({
@@ -42,7 +43,7 @@ export class SessionViewModel extends EventEmitter {
         if (this._currentRoomViewModel) {
             this._currentRoomViewModel.dispose();
             this._currentRoomViewModel = null;
-            this.emit("change", "currentRoom");
+            this.emitChange("currentRoom");
         }
     }
 
@@ -50,13 +51,13 @@ export class SessionViewModel extends EventEmitter {
         if (this._currentRoomViewModel) {
             this._currentRoomViewModel.dispose();
         }
-        this._currentRoomViewModel = new RoomViewModel({
+        this._currentRoomViewModel = new RoomViewModel(this.childOptions({
             room,
             ownUserId: this._session.user.id,
             closeCallback: () => this._closeCurrentRoom(),
-        });
+        }));
         this._currentRoomViewModel.load();
-        this.emit("change", "currentRoom");
+        this.emitChange("currentRoom");
     }
 }
 

src/domain/session/SyncStatusViewModel.js

@@ -1,6 +1,6 @@
-import {EventEmitter} from "../../utils/EventEmitter.js";
+import {ViewModel} from "../ViewModel.js";
 
-export class SyncStatusViewModel extends EventEmitter {
+export class SyncStatusViewModel extends ViewModel {
     constructor(sync) {
         super();
         this._sync = sync;
@@ -13,7 +13,7 @@ export class SyncStatusViewModel extends EventEmitter {
         } else if (status === "started") {
             this._error = null;
         }
-        this.emit("change");
+        this.emitChange();
     }
 
     onFirstSubscriptionAdded(name) {
@@ -30,7 +30,7 @@ export class SyncStatusViewModel extends EventEmitter {
 
     trySync() {
         this._sync.start();
-        this.emit("change");
+        this.emitChange();
     }
 
     get status() {

src/domain/session/room/RoomViewModel.js

@@ -1,10 +1,11 @@
-import {EventEmitter} from "../../../utils/EventEmitter.js";
 import {TimelineViewModel} from "./timeline/TimelineViewModel.js";
 import {avatarInitials} from "../avatar.js";
+import {ViewModel} from "../../ViewModel.js";
 
-export class RoomViewModel extends EventEmitter {
+export class RoomViewModel extends ViewModel {
-    constructor({room, ownUserId, closeCallback}) {
+    constructor(options) {
-        super();
+        super(options);
+        const {room, ownUserId, closeCallback} = options;
         this._room = room;
         this._ownUserId = ownUserId;
         this._timeline = null;
@@ -19,12 +20,16 @@ export class RoomViewModel extends EventEmitter {
         this._room.on("change", this._onRoomChange);
         try {
             this._timeline = await this._room.openTimeline();
-            this._timelineVM = new TimelineViewModel(this._room, this._timeline, this._ownUserId);
+            this._timelineVM = new TimelineViewModel(this.childOptions({
-            this.emit("change", "timelineViewModel");
+                room: this._room,
+                timeline: this._timeline,
+                ownUserId: this._ownUserId,
+            }));
+            this.emitChange("timelineViewModel");
         } catch (err) {
             console.error(`room.openTimeline(): ${err.message}:\n${err.stack}`);
             this._timelineError = err;
-            this.emit("change", "error");
+            this.emitChange("error");
         }
     }
 
@@ -43,7 +48,7 @@ export class RoomViewModel extends EventEmitter {
     // room doesn't tell us yet which fields changed,
     // so emit all fields originating from summary
     _onRoomChange() {
-        this.emit("change", "name");
+        this.emitChange("name");
     }
 
     get name() {
@@ -76,7 +81,7 @@ export class RoomViewModel extends EventEmitter {
                 console.error(`room.sendMessage(): ${err.message}:\n${err.stack}`);
                 this._sendError = err;
                 this._timelineError = null;
-                this.emit("change", "error");
+                this.emitChange("error");
                 return false;
             }
             return true;

src/domain/session/room/timeline/TimelineViewModel.js

@@ -18,7 +18,7 @@ import {TilesCollection} from "./TilesCollection.js";
 import {tilesCreator} from "./tilesCreator.js";
 
 export class TimelineViewModel {
-    constructor(room, timeline, ownUserId) {
+    constructor({room, timeline, ownUserId}) {
         this._timeline = timeline;
         // once we support sending messages we could do
         // timeline.entries.concat(timeline.pendingEvents)