Wire space switch shortcut via dispatcher to prevent app load explosion due to skinning

src/dispatcher/actions.ts

@@ -138,4 +138,9 @@ export enum Action {
      * Fired when an upload is cancelled by the user. Should be used with UploadCanceledPayload.
      */
     UploadCanceled = "upload_canceled",
+
+    /**
+     * Switches space. Should be used with SwitchSpacePayload.
+     */
+    SwitchSpace = "switch_space",
 }

src/dispatcher/payloads/SwitchSpacePayload.ts

@@ -0,0 +1,27 @@
+/*
+Copyright 2021 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 { ActionPayload } from "../payloads";
+import { Action } from "../actions";
+
+export interface SwitchSpacePayload extends ActionPayload {
+    action: Action.SwitchSpace;
+
+    /**
+     * The number of the space to switch to, 1-indexed, 0 is Home.
+     */
+    num: number;
+}