Improve RovingTabIndex & Room List filtering performance (#6987)

src/accessibility/RovingTabIndex.tsx

@@ -24,6 +24,7 @@ import React, {
     useReducer,
     Reducer,
     Dispatch,
+    RefObject,
 } from "react";
 
 import { Key } from "../Keyboard";
@@ -63,7 +64,7 @@ const RovingTabIndexContext = createContext<IContext>({
 });
 RovingTabIndexContext.displayName = "RovingTabIndexContext";
 
-enum Type {
+export enum Type {
     Register = "REGISTER",
     Unregister = "UNREGISTER",
     SetFocus = "SET_FOCUS",
@@ -76,73 +77,67 @@ interface IAction {
     };
 }
 
-const reducer = (state: IState, action: IAction) => {
+export const reducer = (state: IState, action: IAction) => {
     switch (action.type) {
         case Type.Register: {
-            if (state.refs.length === 0) {
+            let left = 0;
+            let right = state.refs.length - 1;
+            let index = state.refs.length; // by default append to the end
+
+            // do a binary search to find the right slot
+            while (left <= right) {
+                index = Math.floor((left + right) / 2);
+                const ref = state.refs[index];
+
+                if (ref === action.payload.ref) {
+                    return state; // already in refs, this should not happen
+                }
+
+                if (action.payload.ref.current.compareDocumentPosition(ref.current) & DOCUMENT_POSITION_PRECEDING) {
+                    left = ++index;
+                } else {
+                    right = index - 1;
+                }
+            }
+
+            if (!state.activeRef) {
                 // Our list of refs was empty, set activeRef to this first item
-                return {
+                state.activeRef = action.payload.ref;
-                    ...state,
-                    activeRef: action.payload.ref,
-                    refs: [action.payload.ref],
-                };
-            }
-
-            if (state.refs.includes(action.payload.ref)) {
-                return state; // already in refs, this should not happen
-            }
-
-            // find the index of the first ref which is not preceding this one in DOM order
-            let newIndex = state.refs.findIndex(ref => {
-                return ref.current.compareDocumentPosition(action.payload.ref.current) & DOCUMENT_POSITION_PRECEDING;
-            });
-
-            if (newIndex < 0) {
-                newIndex = state.refs.length; // append to the end
             }
 
             // update the refs list
-            return {
+            if (index < state.refs.length) {
-                ...state,
+                state.refs.splice(index, 0, action.payload.ref);
-                refs: [
+            } else {
-                    ...state.refs.slice(0, newIndex),
+                state.refs.push(action.payload.ref);
-                    action.payload.ref,
+            }
-                    ...state.refs.slice(newIndex),
+            return { ...state };
-                ],
-            };
         }
-        case Type.Unregister: {
-            // filter out the ref which we are removing
-            const refs = state.refs.filter(r => r !== action.payload.ref);
 
-            if (refs.length === state.refs.length) {
+        case Type.Unregister: {
+            const oldIndex = state.refs.findIndex(r => r === action.payload.ref);
+
+            if (oldIndex === -1) {
                 return state; // already removed, this should not happen
             }
 
-            if (state.activeRef === action.payload.ref) {
+            if (state.refs.splice(oldIndex, 1)[0] === state.activeRef) {
                 // we just removed the active ref, need to replace it
                 // pick the ref which is now in the index the old ref was in
-                const oldIndex = state.refs.findIndex(r => r === action.payload.ref);
+                const len = state.refs.length;
-                return {
+                state.activeRef = oldIndex >= len ? state.refs[len - 1] : state.refs[oldIndex];
-                    ...state,
-                    activeRef: oldIndex >= refs.length ? refs[refs.length - 1] : refs[oldIndex],
-                    refs,
-                };
             }
 
             // update the refs list
-            return {
+            return { ...state };
-                ...state,
-                refs,
-            };
         }
+
         case Type.SetFocus: {
             // update active ref
-            return {
+            state.activeRef = action.payload.ref;
-                ...state,
+            return { ...state };
-                activeRef: action.payload.ref,
-            };
         }
+
         default:
             return state;
     }
@@ -151,13 +146,40 @@ const reducer = (state: IState, action: IAction) => {
 interface IProps {
     handleHomeEnd?: boolean;
     handleUpDown?: boolean;
+    handleLeftRight?: boolean;
     children(renderProps: {
         onKeyDownHandler(ev: React.KeyboardEvent);
     });
     onKeyDown?(ev: React.KeyboardEvent, state: IState);
 }
 
-export const RovingTabIndexProvider: React.FC<IProps> = ({ children, handleHomeEnd, handleUpDown, onKeyDown }) => {
+export const findSiblingElement = (
+    refs: RefObject<HTMLElement>[],
+    startIndex: number,
+    backwards = false,
+): RefObject<HTMLElement> => {
+    if (backwards) {
+        for (let i = startIndex; i < refs.length && i >= 0; i--) {
+            if (refs[i].current.offsetParent !== null) {
+                return refs[i];
+            }
+        }
+    } else {
+        for (let i = startIndex; i < refs.length && i >= 0; i++) {
+            if (refs[i].current.offsetParent !== null) {
+                return refs[i];
+            }
+        }
+    }
+};
+
+export const RovingTabIndexProvider: React.FC<IProps> = ({
+    children,
+    handleHomeEnd,
+    handleUpDown,
+    handleLeftRight,
+    onKeyDown,
+}) => {
     const [state, dispatch] = useReducer<Reducer<IState, IAction>>(reducer, {
         activeRef: null,
         refs: [],
@@ -166,6 +188,13 @@ export const RovingTabIndexProvider: React.FC<IProps> = ({ children, handleHomeE
     const context = useMemo<IContext>(() => ({ state, dispatch }), [state]);
 
     const onKeyDownHandler = useCallback((ev) => {
+        if (onKeyDown) {
+            onKeyDown(ev, context.state);
+            if (ev.defaultPrevented) {
+                return;
+            }
+        }
+
         let handled = false;
         // Don't interfere with input default keydown behaviour
         if (ev.target.tagName !== "INPUT" && ev.target.tagName !== "TEXTAREA") {
@@ -174,43 +203,37 @@ export const RovingTabIndexProvider: React.FC<IProps> = ({ children, handleHomeE
                 case Key.HOME:
                     if (handleHomeEnd) {
                         handled = true;
-                        // move focus to first item
+                        // move focus to first (visible) item
-                        if (context.state.refs.length > 0) {
+                        findSiblingElement(context.state.refs, 0)?.current?.focus();
-                            context.state.refs[0].current.focus();
-                        }
                     }
                     break;
 
                 case Key.END:
                     if (handleHomeEnd) {
                         handled = true;
-                        // move focus to last item
+                        // move focus to last (visible) item
-                        if (context.state.refs.length > 0) {
+                        findSiblingElement(context.state.refs, context.state.refs.length - 1, true)?.current?.focus();
-                            context.state.refs[context.state.refs.length - 1].current.focus();
-                        }
                     }
                     break;
 
                 case Key.ARROW_UP:
-                    if (handleUpDown) {
+                case Key.ARROW_RIGHT:
+                    if ((ev.key === Key.ARROW_UP && handleUpDown) || (ev.key === Key.ARROW_RIGHT && handleLeftRight)) {
                         handled = true;
                         if (context.state.refs.length > 0) {
                             const idx = context.state.refs.indexOf(context.state.activeRef);
-                            if (idx > 0) {
+                            findSiblingElement(context.state.refs, idx - 1)?.current?.focus();
-                                context.state.refs[idx - 1].current.focus();
-                            }
                         }
                     }
                     break;
 
                 case Key.ARROW_DOWN:
-                    if (handleUpDown) {
+                case Key.ARROW_LEFT:
+                    if ((ev.key === Key.ARROW_DOWN && handleUpDown) || (ev.key === Key.ARROW_LEFT && handleLeftRight)) {
                         handled = true;
                         if (context.state.refs.length > 0) {
                             const idx = context.state.refs.indexOf(context.state.activeRef);
-                            if (idx < context.state.refs.length - 1) {
+                            findSiblingElement(context.state.refs, idx + 1, true)?.current?.focus();
-                                context.state.refs[idx + 1].current.focus();
-                            }
                         }
                     }
                     break;
@@ -220,10 +243,8 @@ export const RovingTabIndexProvider: React.FC<IProps> = ({ children, handleHomeE
         if (handled) {
             ev.preventDefault();
             ev.stopPropagation();
-        } else if (onKeyDown) {
-            return onKeyDown(ev, context.state);
         }
-    }, [context.state, onKeyDown, handleHomeEnd, handleUpDown]);
+    }, [context.state, onKeyDown, handleHomeEnd, handleUpDown, handleLeftRight]);
 
     return <RovingTabIndexContext.Provider value={context}>
         { children({ onKeyDownHandler }) }

src/accessibility/Toolbar.tsx

@@ -16,7 +16,7 @@ limitations under the License.
 
 import React from "react";
 
-import { IState, RovingTabIndexProvider } from "./RovingTabIndex";
+import { RovingTabIndexProvider } from "./RovingTabIndex";
 import { Key } from "../Keyboard";
 
 interface IProps extends Omit<React.HTMLProps<HTMLDivElement>, "onKeyDown"> {
@@ -26,7 +26,7 @@ interface IProps extends Omit<React.HTMLProps<HTMLDivElement>, "onKeyDown"> {
 // https://www.w3.org/TR/wai-aria-practices-1.1/#toolbar
 // All buttons passed in children must use RovingTabIndex to set `onFocus`, `isActive`, `ref`
 const Toolbar: React.FC<IProps> = ({ children, ...props }) => {
-    const onKeyDown = (ev: React.KeyboardEvent, state: IState) => {
+    const onKeyDown = (ev: React.KeyboardEvent) => {
         const target = ev.target as HTMLElement;
         // Don't interfere with input default keydown behaviour
         if (target.tagName === "INPUT") return;
@@ -42,15 +42,6 @@ const Toolbar: React.FC<IProps> = ({ children, ...props }) => {
                 }
                 break;
 
-            case Key.ARROW_LEFT:
-            case Key.ARROW_RIGHT:
-                if (state.refs.length > 0) {
-                    const i = state.refs.findIndex(r => r === state.activeRef);
-                    const delta = ev.key === Key.ARROW_RIGHT ? 1 : -1;
-                    state.refs.slice((i + delta) % state.refs.length)[0].current.focus();
-                }
-                break;
-
             default:
                 handled = false;
         }

src/components/structures/ContextMenu.tsx

@@ -249,6 +249,8 @@ export class ContextMenu extends React.PureComponent<IProps, IState> {
         let handled = true;
 
         switch (ev.key) {
+            // XXX: this is imitating roving behaviour, it should really use the RovingTabIndex utils
+            // to inherit proper handling of unmount edge cases
             case Key.TAB:
             case Key.ESCAPE:
             case Key.ARROW_LEFT: // close on left and right arrows too for when it is a context menu on a <Toolbar />

src/components/structures/LeftPanel.tsx

@@ -40,6 +40,7 @@ import { replaceableComponent } from "../../utils/replaceableComponent";
 import SpaceStore, { UPDATE_SELECTED_SPACE } from "../../stores/SpaceStore";
 import { getKeyBindingsManager, RoomListAction } from "../../KeyBindingsManager";
 import UIStore from "../../stores/UIStore";
+import { findSiblingElement, IState as IRovingTabIndexState } from "../../accessibility/RovingTabIndex";
 
 interface IProps {
     isMinimized: boolean;
@@ -51,19 +52,12 @@ interface IState {
     activeSpace?: Room;
 }
 
-// List of CSS classes which should be included in keyboard navigation within the room list
-const cssClasses = [
-    "mx_RoomSearch_input",
-    "mx_RoomSearch_minimizedHandle", // minimized <RoomSearch />
-    "mx_RoomSublist_headerText",
-    "mx_RoomTile",
-    "mx_RoomSublist_showNButton",
-];
-
 @replaceableComponent("structures.LeftPanel")
 export default class LeftPanel extends React.Component<IProps, IState> {
-    private ref: React.RefObject<HTMLDivElement> = createRef();
+    private ref = createRef<HTMLDivElement>();
-    private listContainerRef: React.RefObject<HTMLDivElement> = createRef();
+    private listContainerRef = createRef<HTMLDivElement>();
+    private roomSearchRef = createRef<RoomSearch>();
+    private roomListRef = createRef<RoomList>();
     private focusedElement = null;
     private isDoingStickyHeaders = false;
 
@@ -283,16 +277,25 @@ export default class LeftPanel extends React.Component<IProps, IState> {
         this.focusedElement = null;
     };
 
-    private onKeyDown = (ev: React.KeyboardEvent) => {
+    private onKeyDown = (ev: React.KeyboardEvent, state?: IRovingTabIndexState) => {
         if (!this.focusedElement) return;
 
         const action = getKeyBindingsManager().getRoomListAction(ev);
         switch (action) {
             case RoomListAction.NextRoom:
+                if (!state) {
+                    ev.stopPropagation();
+                    ev.preventDefault();
+                    this.roomListRef.current?.focus();
+                }
+                break;
+
             case RoomListAction.PrevRoom:
-                ev.stopPropagation();
+                if (state && state.activeRef === findSiblingElement(state.refs, 0)) {
-                ev.preventDefault();
+                    ev.stopPropagation();
-                this.onMoveFocus(action === RoomListAction.PrevRoom);
+                    ev.preventDefault();
+                    this.roomSearchRef.current?.focus();
+                }
                 break;
         }
     };
@@ -305,45 +308,6 @@ export default class LeftPanel extends React.Component<IProps, IState> {
         }
     };
 
-    private onMoveFocus = (up: boolean) => {
-        let element = this.focusedElement;
-
-        let descending = false; // are we currently descending or ascending through the DOM tree?
-        let classes: DOMTokenList;
-
-        do {
-            const child = up ? element.lastElementChild : element.firstElementChild;
-            const sibling = up ? element.previousElementSibling : element.nextElementSibling;
-
-            if (descending) {
-                if (child) {
-                    element = child;
-                } else if (sibling) {
-                    element = sibling;
-                } else {
-                    descending = false;
-                    element = element.parentElement;
-                }
-            } else {
-                if (sibling) {
-                    element = sibling;
-                    descending = true;
-                } else {
-                    element = element.parentElement;
-                }
-            }
-
-            if (element) {
-                classes = element.classList;
-            }
-        } while (element && (!cssClasses.some(c => classes.contains(c)) || element.offsetParent === null));
-
-        if (element) {
-            element.focus();
-            this.focusedElement = element;
-        }
-    };
-
     private renderHeader(): React.ReactNode {
         return (
             <div className="mx_LeftPanel_userHeader">
@@ -388,7 +352,7 @@ export default class LeftPanel extends React.Component<IProps, IState> {
             >
                 <RoomSearch
                     isMinimized={this.props.isMinimized}
-                    onKeyDown={this.onKeyDown}
+                    ref={this.roomSearchRef}
                     onSelectRoom={this.selectRoom}
                 />
 
@@ -417,6 +381,7 @@ export default class LeftPanel extends React.Component<IProps, IState> {
             activeSpace={this.state.activeSpace}
             onResize={this.refreshStickyHeaders}
             onListCollapse={this.refreshStickyHeaders}
+            ref={this.roomListRef}
         />;
 
         const containerClasses = classNames({

src/components/structures/RoomSearch.tsx

@@ -32,7 +32,6 @@ import SpaceStore, { UPDATE_SELECTED_SPACE, UPDATE_TOP_LEVEL_SPACES } from "../.
 
 interface IProps {
     isMinimized: boolean;
-    onKeyDown(ev: React.KeyboardEvent): void;
     /**
      * @returns true if a room has been selected and the search field should be cleared
      */
@@ -133,11 +132,6 @@ export default class RoomSearch extends React.PureComponent<IProps, IState> {
                 this.clearInput();
                 defaultDispatcher.fire(Action.FocusSendMessageComposer);
                 break;
-            case RoomListAction.NextRoom:
-            case RoomListAction.PrevRoom:
-                // we don't handle these actions here put pass the event on to the interested party (LeftPanel)
-                this.props.onKeyDown(ev);
-                break;
             case RoomListAction.SelectRoom: {
                 const shouldClear = this.props.onSelectRoom();
                 if (shouldClear) {
@@ -151,6 +145,10 @@ export default class RoomSearch extends React.PureComponent<IProps, IState> {
         }
     };
 
+    public focus(): void {
+        this.inputRef.current?.focus();
+    }
+
     public render(): React.ReactNode {
         const classes = classNames({
             'mx_RoomSearch': true,

src/components/views/rooms/RoomList.tsx

@@ -14,14 +14,14 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { ReactComponentElement } from "react";
+import React, { createRef, ReactComponentElement } from "react";
 import { Dispatcher } from "flux";
 import { Room } from "matrix-js-sdk/src/models/room";
 import * as fbEmitter from "fbemitter";
 import { EventType } from "matrix-js-sdk/src/@types/event";
 
 import { _t, _td } from "../../../languageHandler";
-import { RovingTabIndexProvider } from "../../../accessibility/RovingTabIndex";
+import { RovingTabIndexProvider, IState as IRovingTabIndexState } from "../../../accessibility/RovingTabIndex";
 import ResizeNotifier from "../../../utils/ResizeNotifier";
 import RoomListStore, { LISTS_UPDATE_EVENT } from "../../../stores/room-list/RoomListStore";
 import RoomViewStore from "../../../stores/RoomViewStore";
@@ -54,7 +54,7 @@ import { UIComponent } from "../../../settings/UIFeature";
 import { JoinRule } from "matrix-js-sdk/src/@types/partials";
 
 interface IProps {
-    onKeyDown: (ev: React.KeyboardEvent) => void;
+    onKeyDown: (ev: React.KeyboardEvent, state: IRovingTabIndexState) => void;
     onFocus: (ev: React.FocusEvent) => void;
     onBlur: (ev: React.FocusEvent) => void;
     onResize: () => void;
@@ -249,6 +249,7 @@ export default class RoomList extends React.PureComponent<IProps, IState> {
     private dispatcherRef;
     private customTagStoreRef;
     private roomStoreToken: fbEmitter.EventSubscription;
+    private treeRef = createRef<HTMLDivElement>();
 
     constructor(props: IProps) {
         super(props);
@@ -505,6 +506,12 @@ export default class RoomList extends React.PureComponent<IProps, IState> {
             });
     }
 
+    public focus(): void {
+        // focus the first focusable element in this aria treeview widget
+        [...this.treeRef.current?.querySelectorAll<HTMLElement>('[role="treeitem"]')]
+            .find(e => e.offsetParent !== null)?.focus();
+    }
+
     public render() {
         const cli = MatrixClientPeg.get();
         const userId = cli.getUserId();
@@ -584,7 +591,7 @@ export default class RoomList extends React.PureComponent<IProps, IState> {
 
         const sublists = this.renderSublists();
         return (
-            <RovingTabIndexProvider handleHomeEnd={true} onKeyDown={this.props.onKeyDown}>
+            <RovingTabIndexProvider handleHomeEnd handleUpDown onKeyDown={this.props.onKeyDown}>
                 { ({ onKeyDownHandler }) => (
                     <div
                         onFocus={this.props.onFocus}
@@ -593,6 +600,7 @@ export default class RoomList extends React.PureComponent<IProps, IState> {
                         className="mx_RoomList"
                         role="tree"
                         aria-label={_t("Rooms")}
+                        ref={this.treeRef}
                     >
                         { sublists }
                         { explorePrompt }

src/components/views/spaces/SpacePanel.tsx

@@ -43,7 +43,6 @@ import SpaceStore, {
 } from "../../../stores/SpaceStore";
 import AutoHideScrollbar from "../../structures/AutoHideScrollbar";
 import { RovingTabIndexProvider } from "../../../accessibility/RovingTabIndex";
-import { Key } from "../../../Keyboard";
 import { RoomNotificationStateStore } from "../../../stores/notifications/RoomNotificationStateStore";
 import SpaceContextMenu from "../context_menus/SpaceContextMenu";
 import IconizedContextMenu, {
@@ -228,75 +227,12 @@ const SpacePanel = () => {
         return () => UIStore.instance.stopTrackingElementDimensions("SpacePanel");
     }, []);
 
-    const onKeyDown = (ev: React.KeyboardEvent) => {
-        if (ev.defaultPrevented) return;
-
-        let handled = true;
-
-        switch (ev.key) {
-            case Key.ARROW_UP:
-                onMoveFocus(ev.target as Element, true);
-                break;
-            case Key.ARROW_DOWN:
-                onMoveFocus(ev.target as Element, false);
-                break;
-            default:
-                handled = false;
-        }
-
-        if (handled) {
-            // consume all other keys in context menu
-            ev.stopPropagation();
-            ev.preventDefault();
-        }
-    };
-
-    const onMoveFocus = (element: Element, up: boolean) => {
-        let descending = false; // are we currently descending or ascending through the DOM tree?
-        let classes: DOMTokenList;
-
-        do {
-            const child = up ? element.lastElementChild : element.firstElementChild;
-            const sibling = up ? element.previousElementSibling : element.nextElementSibling;
-
-            if (descending) {
-                if (child) {
-                    element = child;
-                } else if (sibling) {
-                    element = sibling;
-                } else {
-                    descending = false;
-                    element = element.parentElement;
-                }
-            } else {
-                if (sibling) {
-                    element = sibling;
-                    descending = true;
-                } else {
-                    element = element.parentElement;
-                }
-            }
-
-            if (element) {
-                if (element.classList.contains("mx_ContextualMenu")) { // we hit the top
-                    element = up ? element.lastElementChild : element.firstElementChild;
-                    descending = true;
-                }
-                classes = element.classList;
-            }
-        } while (element && !classes.contains("mx_SpaceButton"));
-
-        if (element) {
-            (element as HTMLElement).focus();
-        }
-    };
-
     return (
         <DragDropContext onDragEnd={result => {
             if (!result.destination) return; // dropped outside the list
             SpaceStore.instance.moveRootSpace(result.source.index, result.destination.index);
         }}>
-            <RovingTabIndexProvider handleHomeEnd={true} onKeyDown={onKeyDown}>
+            <RovingTabIndexProvider handleHomeEnd handleUpDown>
                 { ({ onKeyDownHandler }) => (
                     <ul
                         className={classNames("mx_SpacePanel", { collapsed: isPanelCollapsed })}

test/accessibility/RovingTabIndex-test.js

@@ -1,118 +0,0 @@
-/*
-Copyright 2020 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 '../skinned-sdk'; // Must be first for skinning to work
-import React from "react";
-import { mount } from "enzyme";
-
-import {
-    RovingTabIndexProvider,
-    RovingTabIndexWrapper,
-    useRovingTabIndex,
-} from "../../src/accessibility/RovingTabIndex";
-
-const Button = (props) => {
-    const [onFocus, isActive, ref] = useRovingTabIndex();
-    return <button {...props} onFocus={onFocus} tabIndex={isActive ? 0 : -1} ref={ref} />;
-};
-
-const checkTabIndexes = (buttons, expectations) => {
-    expect(buttons.length).toBe(expectations.length);
-    for (let i = 0; i < buttons.length; i++) {
-        expect(buttons.at(i).prop("tabIndex")).toBe(expectations[i]);
-    }
-};
-
-// give the buttons keys for the fibre reconciler to not treat them all as the same
-const button1 = <Button key={1}>a</Button>;
-const button2 = <Button key={2}>b</Button>;
-const button3 = <Button key={3}>c</Button>;
-const button4 = <Button key={4}>d</Button>;
-
-describe("RovingTabIndex", () => {
-    it("RovingTabIndexProvider renders children as expected", () => {
-        const wrapper = mount(<RovingTabIndexProvider>
-            { () => <div><span>Test</span></div> }
-        </RovingTabIndexProvider>);
-        expect(wrapper.text()).toBe("Test");
-        expect(wrapper.html()).toBe('<div><span>Test</span></div>');
-    });
-
-    it("RovingTabIndexProvider works as expected with useRovingTabIndex", () => {
-        const wrapper = mount(<RovingTabIndexProvider>
-            { () => <React.Fragment>
-                { button1 }
-                { button2 }
-                { button3 }
-            </React.Fragment> }
-        </RovingTabIndexProvider>);
-
-        // should begin with 0th being active
-        checkTabIndexes(wrapper.find("button"), [0, -1, -1]);
-
-        // focus on 2nd button and test it is the only active one
-        wrapper.find("button").at(2).simulate("focus");
-        wrapper.update();
-        checkTabIndexes(wrapper.find("button"), [-1, -1, 0]);
-
-        // focus on 1st button and test it is the only active one
-        wrapper.find("button").at(1).simulate("focus");
-        wrapper.update();
-        checkTabIndexes(wrapper.find("button"), [-1, 0, -1]);
-
-        // check that the active button does not change even on an explicit blur event
-        wrapper.find("button").at(1).simulate("blur");
-        wrapper.update();
-        checkTabIndexes(wrapper.find("button"), [-1, 0, -1]);
-
-        // update the children, it should remain on the same button
-        wrapper.setProps({
-            children: () => [button1, button4, button2, button3],
-        });
-        wrapper.update();
-        checkTabIndexes(wrapper.find("button"), [-1, -1, 0, -1]);
-
-        // update the children, remove the active button, it should move to the next one
-        wrapper.setProps({
-            children: () => [button1, button4, button3],
-        });
-        wrapper.update();
-        checkTabIndexes(wrapper.find("button"), [-1, -1, 0]);
-    });
-
-    it("RovingTabIndexProvider works as expected with RovingTabIndexWrapper", () => {
-        const wrapper = mount(<RovingTabIndexProvider>
-            { () => <React.Fragment>
-                { button1 }
-                { button2 }
-                <RovingTabIndexWrapper>
-                    { ({ onFocus, isActive, ref }) =>
-                        <button onFocus={onFocus} tabIndex={isActive ? 0 : -1} ref={ref}>.</button>
-                    }
-                </RovingTabIndexWrapper>
-            </React.Fragment> }
-        </RovingTabIndexProvider>);
-
-        // should begin with 0th being active
-        checkTabIndexes(wrapper.find("button"), [0, -1, -1]);
-
-        // focus on 2nd button and test it is the only active one
-        wrapper.find("button").at(2).simulate("focus");
-        wrapper.update();
-        checkTabIndexes(wrapper.find("button"), [-1, -1, 0]);
-    });
-});
-

test/accessibility/RovingTabIndex-test.tsx

@@ -0,0 +1,341 @@
+/*
+Copyright 2020 - 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 '../skinned-sdk'; // Must be first for skinning to work
+import * as React from "react";
+import { mount, ReactWrapper } from "enzyme";
+
+import {
+    IState,
+    reducer,
+    RovingTabIndexProvider,
+    RovingTabIndexWrapper,
+    Type,
+    useRovingTabIndex,
+} from "../../src/accessibility/RovingTabIndex";
+
+const Button = (props) => {
+    const [onFocus, isActive, ref] = useRovingTabIndex();
+    return <button {...props} onFocus={onFocus} tabIndex={isActive ? 0 : -1} ref={ref} />;
+};
+
+const checkTabIndexes = (buttons: ReactWrapper, expectations: number[]) => {
+    expect(buttons.length).toBe(expectations.length);
+    for (let i = 0; i < buttons.length; i++) {
+        expect(buttons.at(i).prop("tabIndex")).toBe(expectations[i]);
+    }
+};
+
+// give the buttons keys for the fibre reconciler to not treat them all as the same
+const button1 = <Button key={1}>a</Button>;
+const button2 = <Button key={2}>b</Button>;
+const button3 = <Button key={3}>c</Button>;
+const button4 = <Button key={4}>d</Button>;
+
+describe("RovingTabIndex", () => {
+    it("RovingTabIndexProvider renders children as expected", () => {
+        const wrapper = mount(<RovingTabIndexProvider>
+            { () => <div><span>Test</span></div> }
+        </RovingTabIndexProvider>);
+        expect(wrapper.text()).toBe("Test");
+        expect(wrapper.html()).toBe('<div><span>Test</span></div>');
+    });
+
+    it("RovingTabIndexProvider works as expected with useRovingTabIndex", () => {
+        const wrapper = mount(<RovingTabIndexProvider>
+            { () => <React.Fragment>
+                { button1 }
+                { button2 }
+                { button3 }
+            </React.Fragment> }
+        </RovingTabIndexProvider>);
+
+        // should begin with 0th being active
+        checkTabIndexes(wrapper.find("button"), [0, -1, -1]);
+
+        // focus on 2nd button and test it is the only active one
+        wrapper.find("button").at(2).simulate("focus");
+        wrapper.update();
+        checkTabIndexes(wrapper.find("button"), [-1, -1, 0]);
+
+        // focus on 1st button and test it is the only active one
+        wrapper.find("button").at(1).simulate("focus");
+        wrapper.update();
+        checkTabIndexes(wrapper.find("button"), [-1, 0, -1]);
+
+        // check that the active button does not change even on an explicit blur event
+        wrapper.find("button").at(1).simulate("blur");
+        wrapper.update();
+        checkTabIndexes(wrapper.find("button"), [-1, 0, -1]);
+
+        // update the children, it should remain on the same button
+        wrapper.setProps({
+            children: () => [button1, button4, button2, button3],
+        });
+        wrapper.update();
+        checkTabIndexes(wrapper.find("button"), [-1, -1, 0, -1]);
+
+        // update the children, remove the active button, it should move to the next one
+        wrapper.setProps({
+            children: () => [button1, button4, button3],
+        });
+        wrapper.update();
+        checkTabIndexes(wrapper.find("button"), [-1, -1, 0]);
+    });
+
+    it("RovingTabIndexProvider works as expected with RovingTabIndexWrapper", () => {
+        const wrapper = mount(<RovingTabIndexProvider>
+            { () => <React.Fragment>
+                { button1 }
+                { button2 }
+                <RovingTabIndexWrapper>
+                    { ({ onFocus, isActive, ref }) =>
+                        <button onFocus={onFocus} tabIndex={isActive ? 0 : -1} ref={ref}>.</button>
+                    }
+                </RovingTabIndexWrapper>
+            </React.Fragment> }
+        </RovingTabIndexProvider>);
+
+        // should begin with 0th being active
+        checkTabIndexes(wrapper.find("button"), [0, -1, -1]);
+
+        // focus on 2nd button and test it is the only active one
+        wrapper.find("button").at(2).simulate("focus");
+        wrapper.update();
+        checkTabIndexes(wrapper.find("button"), [-1, -1, 0]);
+    });
+
+    describe("reducer functions as expected", () => {
+        it("SetFocus works as expected", () => {
+            const ref1 = React.createRef<HTMLElement>();
+            const ref2 = React.createRef<HTMLElement>();
+            expect(reducer({
+                activeRef: ref1,
+                refs: [ref1, ref2],
+            }, {
+                type: Type.SetFocus,
+                payload: {
+                    ref: ref2,
+                },
+            })).toStrictEqual({
+                activeRef: ref2,
+                refs: [ref1, ref2],
+            });
+        });
+
+        it("Unregister works as expected", () => {
+            const ref1 = React.createRef<HTMLElement>();
+            const ref2 = React.createRef<HTMLElement>();
+            const ref3 = React.createRef<HTMLElement>();
+            const ref4 = React.createRef<HTMLElement>();
+
+            let state: IState = {
+                activeRef: null,
+                refs: [ref1, ref2, ref3, ref4],
+            };
+
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref2,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: null,
+                refs: [ref1, ref3, ref4],
+            });
+
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref3,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: null,
+                refs: [ref1, ref4],
+            });
+
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref4,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: null,
+                refs: [ref1],
+            });
+
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref1,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: null,
+                refs: [],
+            });
+        });
+
+        it("Register works as expected", () => {
+            const ref1 = React.createRef<HTMLElement>();
+            const ref2 = React.createRef<HTMLElement>();
+            const ref3 = React.createRef<HTMLElement>();
+            const ref4 = React.createRef<HTMLElement>();
+
+            mount(<React.Fragment>
+                <span ref={ref1} />
+                <span ref={ref2} />
+                <span ref={ref3} />
+                <span ref={ref4} />
+            </React.Fragment>);
+
+            let state: IState = {
+                activeRef: null,
+                refs: [],
+            };
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref1,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref1,
+                refs: [ref1],
+            });
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref1,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref1,
+                refs: [ref1],
+            });
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref2,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref1,
+                refs: [ref1, ref2],
+            });
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref3,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref1,
+                refs: [ref1, ref2, ref3],
+            });
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref4,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref1,
+                refs: [ref1, ref2, ref3, ref4],
+            });
+
+            // test that the automatic focus switch works for unmounting
+            state = reducer(state, {
+                type: Type.SetFocus,
+                payload: {
+                    ref: ref2,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref2,
+                refs: [ref1, ref2, ref3, ref4],
+            });
+
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref2,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref3,
+                refs: [ref1, ref3, ref4],
+            });
+
+            // test that the insert into the middle works as expected
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref2,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref3,
+                refs: [ref1, ref2, ref3, ref4],
+            });
+
+            // test that insertion at the edges works
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref1,
+                },
+            });
+            state = reducer(state, {
+                type: Type.Unregister,
+                payload: {
+                    ref: ref4,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref3,
+                refs: [ref2, ref3],
+            });
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref1,
+                },
+            });
+
+            state = reducer(state, {
+                type: Type.Register,
+                payload: {
+                    ref: ref4,
+                },
+            });
+            expect(state).toStrictEqual({
+                activeRef: ref3,
+                refs: [ref1, ref2, ref3, ref4],
+            });
+        });
+    });
+});
+