Exctract into function

src/domain/session/room/RoomViewModel.js

@@ -23,7 +23,7 @@ import {imageToInfo} from "../common.js";
 // TODO: remove fallback so default isn't included in bundle for SDK users that have their custom tileClassForEntry
 // this is a breaking SDK change though to make this option mandatory
 import {tileClassForEntry as defaultTileClassForEntry} from "./timeline/tiles/index";
-import {RoomStatus} from "../../../matrix/room/common";
+import {joinRoom} from "../../../matrix/room/joinRoom";
 
 export class RoomViewModel extends ViewModel {
     constructor(options) {
@@ -200,22 +200,11 @@ export class RoomViewModel extends ViewModel {
     
     async _processCommandJoin(roomName) {
         try {
-            const roomId = await this._options.client.session.joinRoom(roomName);
+            const session = this._options.client.session;
-            const roomStatusObserver = await this._options.client.session.observeRoomStatus(roomId);
+            const roomId = await joinRoom(roomName, session);
-            await roomStatusObserver.waitFor(status => status === RoomStatus.Joined);
             this.navigation.push("room", roomId);
         } catch (err) {
-            let exc;
+            this._sendError = err;
-            if ((err.statusCode ?? err.status) === 400) {
-                exc = new Error(`/join : '${roomName}' was not legal room ID or room alias`);
-            } else if ((err.statusCode ?? err.status) === 404 || (err.statusCode ?? err.status) === 502 || err.message == "Internal Server Error") {
-                exc = new Error(`/join : room '${roomName}' not found`);
-            } else if ((err.statusCode ?? err.status) === 403) {
-                exc = new Error(`/join : you're not invited to join '${roomName}'`);
-            } else {
-                exc = err;
-            }
-            this._sendError = exc;
             this._timelineError = null;
             this.emitChange("error");
         }

src/matrix/room/joinRoom.ts

@@ -0,0 +1,42 @@
+/*
+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 type {Session} from "../Session.js";
+import {RoomStatus} from "./common";
+
+/**
+ * Join a room and wait for it to arrive in the next sync
+ * @param roomId The id of the room to join
+ * @param session A session instance
+ */
+export async function joinRoom(roomId: string, session: Session) {
+    try {
+        const internalRoomId = await session.joinRoom(roomId);
+        const roomStatusObserver = await session.observeRoomStatus(internalRoomId);
+        await roomStatusObserver.waitFor((status: RoomStatus) => status === RoomStatus.Joined);
+        return internalRoomId;
+    }
+    catch (e) {
+        if ((e.statusCode ?? e.status) === 400) {
+            throw new Error(`'${roomId}' is not a legal room ID or alias`);
+        } else if ((e.statusCode ?? e.status) === 404 || (e.statusCode ?? e.status) === 502 || e.message == "Internal Server eor") {
+            throw new Error(`Room '${roomId}' could not be found`);
+        } else if ((e.statusCode ?? e.status) === 403) {
+            throw new Error(`You are not invited to join '${roomId}'`);
+        } else {
+            throw e;
+        }
+    }
+}