Add module APIs to enable widget toggle buttons

packages/element-web-module-api/element-web-module-api.api.md

@@ -5,6 +5,7 @@
 ```ts
 
 import { ComponentType } from 'react';
+import { IWidget } from 'matrix-widget-api';
 import { JSX } from 'react';
 import { ModuleApi } from '@matrix-org/react-sdk-module-api';
 import { Root } from 'react-dom/client';
@@ -56,6 +57,8 @@ export interface Api extends LegacyModuleApiExtension, LegacyCustomisationsApiEx
     readonly rootNode: HTMLElement;
     readonly stores: StoresApi;
     // @alpha
+    readonly widget: WidgetApi;
+    // @alpha
     readonly widgetLifecycle: WidgetLifecycleApi;
 }
 
@@ -107,6 +110,9 @@ export interface ConfigApi {
     get<K extends keyof Config = never>(key?: K): Config | Config[K];
 }
 
+// @alpha
+export type Container = "top" | "right" | "center";
+
 // @alpha
 export interface CustomComponentsApi {
     registerMessageRenderer(eventTypeOrFilter: string | ((mxEvent: MatrixEvent) => boolean), renderer: CustomMessageRenderFunction, hints?: CustomMessageRenderHints): void;
@@ -174,6 +180,7 @@ export interface DirectoryCustomisations {
 // @alpha
 export interface ExtrasApi {
     getVisibleRoomBySpaceKey(spaceKey: string, cb: () => string[]): void;
+    setRoomHeaderButtonCallback(cb: RoomHeaderButtonsCallback): void;
     setSpacePanelItem(spaceKey: string, props: SpacePanelItemProps): void;
 }
 
@@ -358,6 +365,9 @@ export interface Room {
     name: Watchable<string>;
 }
 
+// @alpha
+export type RoomHeaderButtonsCallback = (roomId: string) => JSX.Element | undefined;
+
 // @alpha @deprecated (undocumented)
 export interface RoomListCustomisations<Room> {
     isRoomVisible?(room: Room): boolean;
@@ -436,6 +446,14 @@ export class Watchable<T> {
     watch(listener: (value: T) => void): void;
 }
 
+// @alpha
+export interface WidgetApi {
+    getAppAvatarUrl(app: IWidget, width?: number, height?: number, resizeMethod?: string): string | null;
+    getWidgetsInRoom(roomId: string): IWidget[];
+    isAppInContainer(app: IWidget, container: Container, roomId: string): boolean;
+    moveAppToContainer(app: IWidget, container: Container, roomId: string): void;
+}
+
 // @alpha
 export type WidgetDescriptor = {
     id: string;
@@ -476,4 +494,3 @@ export interface WidgetVariablesCustomisations {
 // (No @packageDocumentation comment for this package)
 
 ```
-

packages/element-web-module-api/package.json

@@ -61,5 +61,8 @@
         "matrix-web-i18n": {
             "optional": true
         }
+    },
+    "dependencies": {
+        "matrix-widget-api": "^1.17.0"
     }
 }

packages/element-web-module-api/src/api/extras.ts

@@ -43,6 +43,15 @@ export interface SpacePanelItemProps {
     onSelected: () => void;
 }
 
+/**
+ * A callback that returns a JSX element representing the buttons.
+ *
+ * @alpha
+ * @param roomId - The ID of the room for which the header is being rendered.
+ * @returns A JSX element representing the buttons to be rendered in the room header, or undefined if no buttons should be rendered.
+ */
+export type RoomHeaderButtonsCallback = (roomId: string) => JSX.Element | undefined;
+
 /**
  * API for inserting extra UI into Element Web.
  * @alpha Subject to change.
@@ -67,4 +76,11 @@ export interface ExtrasApi {
      * @param cb - A callback that returns the list of visible room IDs.
      */
     getVisibleRoomBySpaceKey(spaceKey: string, cb: () => string[]): void;
+
+    /**
+     * Sets the callback to get extra buttons in the room header (which can vary depending on the room being displayed).
+     *
+     * @param cb - A callback that returns a JSX element representing the buttons (see {@link RoomHeaderButtonsCallback}).
+     */
+    setRoomHeaderButtonCallback(cb: RoomHeaderButtonsCallback): void;
 }

packages/element-web-module-api/src/api/index.ts

@@ -1,5 +1,6 @@
 /*
 Copyright 2025 New Vector Ltd.
+Copyright 2026 Element Creations Ltd.
 
 SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE files in the repository root for full details.
@@ -20,6 +21,7 @@ import { type BuiltinsApi } from "./builtins.ts";
 import { type StoresApi } from "./stores.ts";
 import { type ClientApi } from "./client.ts";
 import { type WidgetLifecycleApi } from "./widget-lifecycle.ts";
+import { type WidgetApi } from "./widget.ts";
 
 /**
  * Module interface for modules to implement.
@@ -143,6 +145,13 @@ export interface Api
      */
     readonly widgetLifecycle: WidgetLifecycleApi;
 
+    /**
+     * API for modules to interact with widgets in Element Web, including getting what widgets
+     * are active in a given room.
+     * @alpha Subject to change.
+     */
+    readonly widget: WidgetApi;
+
     /**
      * Create a ReactDOM root for rendering React components.
      * Exposed to allow modules to avoid needing to bundle their own ReactDOM.

packages/element-web-module-api/src/api/widget.ts

@@ -0,0 +1,68 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import { type IWidget } from "matrix-widget-api";
+
+/**
+ * Containers that control where a widget is displayed on the screen.
+ *
+ * "top" is the app drawer, and currently the only sensible value.
+ *
+ * "right" is the right panel, and the default for widgets. Setting
+ * this as a container on a widget is essentially like saying "no
+ * changes needed", though this may change in the future.
+ *
+ * "center" was uncodumented at time of porting this from an enum.
+ * Possibly when a widget replaces the main chat view like element call.
+ *
+ * @alpha Subject to change.
+ */
+export type Container = "top" | "right" | "center";
+
+/**
+ * An API for interfacing with widgets in Element Web, including getting what widgets
+ * are active in a given room.
+ * @alpha Subject to change.
+ */
+export interface WidgetApi {
+    /**
+     * Gets the widgets active in a given room.
+     *
+     * @param roomId - The room to get the widgets for.
+     */
+    getWidgetsInRoom(roomId: string): IWidget[];
+
+    /**
+     * Gets the URL of a widget's avatar, if it has one.
+     *
+     * @param app - The widget to get the avatar URL for.
+     * @param width - Optional width to resize the avatar to.
+     * @param height - Optional height to resize the avatar to.
+     * @param resizeMethod - Optional method to use when resizing the avatar.
+     * @returns The URL of the widget's avatar, or null if it doesn't have one.
+     */
+    getAppAvatarUrl(app: IWidget, width?: number, height?: number, resizeMethod?: string): string | null;
+
+    /**
+     * Checks if a widget is in a specific container in a given room.
+     *
+     * @param app - The widget to check.
+     * @param container - The container to check.
+     * @param roomId - The room to check in.
+     * @returns True if the widget is in the specified container, false otherwise.
+     */
+    isAppInContainer(app: IWidget, container: Container, roomId: string): boolean;
+
+    /**
+     * Moves a widget to a specific container in a given room.
+     *
+     * @param app - The widget to move.
+     * @param container - The container to move the widget to.
+     * @param roomId - The room to move the widget in.
+     */
+    moveAppToContainer(app: IWidget, container: Container, roomId: string): void;
+}

packages/element-web-module-api/src/index.ts

@@ -23,5 +23,6 @@ export type * from "./api/builtins";
 export type * from "./api/stores";
 export type * from "./api/client";
 export type * from "./api/widget-lifecycle";
+export type * from "./api/widget";
 export * from "./api/watchable";
 export type * from "./utils";