Conform more of the codebase to strictNullChecks (#10350

src/@types/common.ts

@@ -52,3 +52,5 @@ export type KeysStartingWith<Input extends object, Str extends string> = {
     // eslint-disable-next-line @typescript-eslint/no-unused-vars
     [P in keyof Input]: P extends `${Str}${infer _X}` ? P : never; // we don't use _X
 }[keyof Input];
+
+export type NonEmptyArray<T> = [T, ...T[]];

src/AddThreepid.ts

@@ -26,7 +26,11 @@ import { SSOAuthEntry } from "./components/views/auth/InteractiveAuthEntryCompon
 import InteractiveAuthDialog from "./components/views/dialogs/InteractiveAuthDialog";
 
 function getIdServerDomain(): string {
-    return MatrixClientPeg.get().idBaseUrl.split("://")[1];
+    const idBaseUrl = MatrixClientPeg.get().idBaseUrl;
+    if (!idBaseUrl) {
+        throw new Error("Identity server not set");
+    }
+    return idBaseUrl.split("://")[1];
 }
 
 export type Binding = {
@@ -190,6 +194,9 @@ export default class AddThreepid {
                 if (this.bind) {
                     const authClient = new IdentityAuthClient();
                     const identityAccessToken = await authClient.getAccessToken();
+                    if (!identityAccessToken) {
+                        throw new Error("No identity access token found");
+                    }
                     await MatrixClientPeg.get().bindThreePid({
                         sid: this.sessionId,
                         client_secret: this.clientSecret,
@@ -279,7 +286,9 @@ export default class AddThreepid {
      * with a "message" property which contains a human-readable message detailing why
      * the request failed.
      */
-    public async haveMsisdnToken(msisdnToken: string): Promise<any[] | undefined> {
+    public async haveMsisdnToken(
+        msisdnToken: string,
+    ): Promise<[success?: boolean, result?: IAuthData | Error | null] | undefined> {
         const authClient = new IdentityAuthClient();
         const supportsSeparateAddAndBind = await MatrixClientPeg.get().doesServerSupportSeparateAddAndBind();
 

src/accessibility/context_menu/ContextMenuButton.tsx

@@ -39,7 +39,7 @@ export const ContextMenuButton: React.FC<IProps> = ({
         <AccessibleButton
             {...props}
             onClick={onClick}
-            onContextMenu={onContextMenu || onClick}
+            onContextMenu={onContextMenu ?? onClick ?? undefined}
             title={label}
             aria-label={label}
             aria-haspopup={true}

src/accessibility/context_menu/ContextMenuTooltipButton.tsx

@@ -37,7 +37,7 @@ export const ContextMenuTooltipButton: React.FC<IProps> = ({
         <AccessibleTooltipButton
             {...props}
             onClick={onClick}
-            onContextMenu={onContextMenu || onClick}
+            onContextMenu={onContextMenu ?? onClick ?? undefined}
             aria-haspopup={true}
             aria-expanded={isExpanded}
             forceHide={isExpanded}

src/actions/RoomListActions.ts

@@ -26,7 +26,7 @@ import { _t } from "../languageHandler";
 import { AsyncActionPayload } from "../dispatcher/payloads";
 import RoomListStore from "../stores/room-list/RoomListStore";
 import { SortAlgorithm } from "../stores/room-list/algorithms/models";
-import { DefaultTagID } from "../stores/room-list/models";
+import { DefaultTagID, TagID } from "../stores/room-list/models";
 import ErrorDialog from "../components/views/dialogs/ErrorDialog";
 
 export default class RoomListActions {
@@ -49,10 +49,10 @@ export default class RoomListActions {
     public static tagRoom(
         matrixClient: MatrixClient,
         room: Room,
-        oldTag: string,
-        newTag: string,
-        oldIndex: number | null,
-        newIndex: number | null,
+        oldTag: TagID | null,
+        newTag: TagID | null,
+        oldIndex?: number,
+        newIndex?: number,
     ): AsyncActionPayload {
         let metaData: Parameters<MatrixClient["setRoomTag"]>[2] | null = null;
 

src/audio/PlaybackQueue.ts

@@ -106,7 +106,7 @@ export class PlaybackQueue {
             // Remove the now-useless clock for some space savings
             this.clockStates.delete(mxEvent.getId()!);
 
-            if (wasLastPlaying) {
+            if (wasLastPlaying && this.currentPlaybackId) {
                 this.recentFullPlays.add(this.currentPlaybackId);
                 const orderClone = arrayFastClone(this.playbackIdOrder);
                 const last = orderClone.pop();
@@ -188,8 +188,8 @@ export class PlaybackQueue {
                 if (order.length === 0 || order[order.length - 1] !== this.currentPlaybackId) {
                     const lastInstance = this.playbacks.get(this.currentPlaybackId);
                     if (
-                        lastInstance.currentState === PlaybackState.Playing ||
-                        lastInstance.currentState === PlaybackState.Paused
+                        lastInstance &&
+                        [PlaybackState.Playing, PlaybackState.Paused].includes(lastInstance.currentState)
                     ) {
                         order.push(this.currentPlaybackId);
                     }

src/boundThreepids.ts

@@ -35,6 +35,9 @@ export async function getThreepidsWithBindStatus(
         try {
             const authClient = new IdentityAuthClient();
             const identityAccessToken = await authClient.getAccessToken({ check: false });
+            if (!identityAccessToken) {
+                throw new Error("No identity access token found");
+            }
 
             // Restructure for lookup query
             const query = threepids.map(({ medium, address }): [string, string] => [medium, address]);

src/components/structures/AutoHideScrollbar.tsx

@@ -29,7 +29,7 @@ export type IProps<T extends keyof JSX.IntrinsicElements> = Omit<DynamicHtmlElem
     onWheel?: (event: WheelEvent) => void;
     style?: React.CSSProperties;
     tabIndex?: number;
-    wrappedRef?: (ref: HTMLDivElement) => void;
+    wrappedRef?: (ref: HTMLDivElement | null) => void;
     children: ReactNode;
 };
 

src/components/structures/FilePanel.tsx

@@ -99,7 +99,7 @@ class FilePanel extends React.Component<IProps, IState> {
 
         const timeline = this.state.timelineSet.getLiveTimeline();
         if (ev.getType() !== "m.room.message") return;
-        if (["m.file", "m.image", "m.video", "m.audio"].indexOf(ev.getContent().msgtype) == -1) {
+        if (!["m.file", "m.image", "m.video", "m.audio"].includes(ev.getContent().msgtype!)) {
             return;
         }
 
@@ -176,7 +176,7 @@ class FilePanel extends React.Component<IProps, IState> {
         // the event index to fulfill the pagination request. Asking the server
         // to paginate won't ever work since the server can't correctly filter
         // out events containing URLs
-        if (client.isRoomEncrypted(roomId) && eventIndex !== null) {
+        if (room && client.isRoomEncrypted(roomId) && eventIndex !== null) {
             return eventIndex.paginateTimelineWindow(room, timelineWindow, direction, limit);
         } else {
             return timelineWindow.paginate(direction, limit);

src/components/structures/GenericDropdownMenu.tsx

@@ -177,19 +177,20 @@ export function GenericDropdownMenu<T>({
             </>
         );
     }
-    const contextMenu = menuDisplayed ? (
-        <ContextMenu
-            onFinished={closeMenu}
-            chevronFace={ChevronFace.Top}
-            wrapperClassName={classNames("mx_GenericDropdownMenu_wrapper", className)}
-            {...aboveLeftOf(button.current.getBoundingClientRect())}
-        >
-            {contextMenuOptions}
-            {AdditionalOptions && (
-                <AdditionalOptions menuDisplayed={menuDisplayed} openMenu={openMenu} closeMenu={closeMenu} />
-            )}
-        </ContextMenu>
-    ) : null;
+    const contextMenu =
+        menuDisplayed && button.current ? (
+            <ContextMenu
+                onFinished={closeMenu}
+                chevronFace={ChevronFace.Top}
+                wrapperClassName={classNames("mx_GenericDropdownMenu_wrapper", className)}
+                {...aboveLeftOf(button.current.getBoundingClientRect())}
+            >
+                {contextMenuOptions}
+                {AdditionalOptions && (
+                    <AdditionalOptions menuDisplayed={menuDisplayed} openMenu={openMenu} closeMenu={closeMenu} />
+                )}
+            </ContextMenu>
+        ) : null;
     return (
         <>
             <ContextMenuButton

src/components/structures/IndicatorScrollbar.tsx

@@ -44,7 +44,7 @@ export default class IndicatorScrollbar<T extends keyof JSX.IntrinsicElements> e
 > {
     private autoHideScrollbar = createRef<AutoHideScrollbar<any>>();
     private scrollElement: HTMLDivElement;
-    private likelyTrackpadUser: boolean = null;
+    private likelyTrackpadUser: boolean | null = null;
     private checkAgainForTrackpad = 0; // ts in milliseconds to recheck this._likelyTrackpadUser
 
     public constructor(props: IProps<T>) {

src/components/structures/LeftPanel.tsx

@@ -271,6 +271,7 @@ export default class LeftPanel extends React.Component<IProps, IState> {
         // add appropriate sticky classes to wrapper so it has
         // the necessary top/bottom padding to put the sticky header in
         const listWrapper = list.parentElement; // .mx_LeftPanel_roomListWrapper
+        if (!listWrapper) return;
         if (lastTopHeader) {
             listWrapper.classList.add("mx_LeftPanel_roomListWrapper_stickyTop");
         } else {

src/components/structures/LegacyCallEventGrouper.ts

@@ -85,23 +85,23 @@ export default class LegacyCallEventGrouper extends EventEmitter {
         );
     }
 
-    private get invite(): MatrixEvent {
+    private get invite(): MatrixEvent | undefined {
         return [...this.events].find((event) => event.getType() === EventType.CallInvite);
     }
 
-    private get hangup(): MatrixEvent {
+    private get hangup(): MatrixEvent | undefined {
         return [...this.events].find((event) => event.getType() === EventType.CallHangup);
     }
 
-    private get reject(): MatrixEvent {
+    private get reject(): MatrixEvent | undefined {
         return [...this.events].find((event) => event.getType() === EventType.CallReject);
     }
 
-    private get selectAnswer(): MatrixEvent {
+    private get selectAnswer(): MatrixEvent | undefined {
         return [...this.events].find((event) => event.getType() === EventType.CallSelectAnswer);
     }
 
-    public get isVoice(): boolean {
+    public get isVoice(): boolean | undefined {
         const invite = this.invite;
         if (!invite) return;
 
@@ -114,7 +114,7 @@ export default class LegacyCallEventGrouper extends EventEmitter {
         return this.call?.hangupReason ?? this.hangup?.getContent()?.reason ?? null;
     }
 
-    public get rejectParty(): string {
+    public get rejectParty(): string | undefined {
         return this.reject?.getSender();
     }
 

src/components/structures/LoggedInView.tsx

@@ -170,7 +170,7 @@ class LoggedInView extends React.Component<IProps, IState> {
         monitorSyncedPushRules(this._matrixClient.getAccountData("m.push_rules"), this._matrixClient);
         this._matrixClient.on(ClientEvent.Sync, this.onSync);
         // Call `onSync` with the current state as well
-        this.onSync(this._matrixClient.getSyncState(), null, this._matrixClient.getSyncStateData());
+        this.onSync(this._matrixClient.getSyncState(), null, this._matrixClient.getSyncStateData() ?? undefined);
         this._matrixClient.on(RoomStateEvent.Events, this.onRoomStateEvents);
 
         this.layoutWatcherRef = SettingsStore.watchSetting("layout", null, this.onCompactLayoutChanged);
@@ -271,11 +271,11 @@ class LoggedInView extends React.Component<IProps, IState> {
     }
 
     private loadResizerPreferences(): void {
-        let lhsSize = parseInt(window.localStorage.getItem("mx_lhs_size"), 10);
+        let lhsSize = parseInt(window.localStorage.getItem("mx_lhs_size")!, 10);
         if (isNaN(lhsSize)) {
             lhsSize = 350;
         }
-        this.resizer.forHandleWithId("lp-resizer").resize(lhsSize);
+        this.resizer.forHandleWithId("lp-resizer")?.resize(lhsSize);
     }
 
     private onAccountData = (event: MatrixEvent): void => {
@@ -291,13 +291,13 @@ class LoggedInView extends React.Component<IProps, IState> {
         });
     };
 
-    private onSync = (syncState: SyncState, oldSyncState?: SyncState, data?: ISyncStateData): void => {
+    private onSync = (syncState: SyncState | null, oldSyncState: SyncState | null, data?: ISyncStateData): void => {
         const oldErrCode = (this.state.syncErrorData?.error as MatrixError)?.errcode;
         const newErrCode = (data?.error as MatrixError)?.errcode;
         if (syncState === oldSyncState && oldErrCode === newErrCode) return;
 
         this.setState({
-            syncErrorData: syncState === SyncState.Error ? data : null,
+            syncErrorData: syncState === SyncState.Error ? data : undefined,
         });
 
         if (oldSyncState === SyncState.Prepared && syncState === SyncState.Syncing) {
@@ -355,7 +355,7 @@ class LoggedInView extends React.Component<IProps, IState> {
             const pinnedEventIds = pinStateEvent.getContent().pinned.slice(0, MAX_PINNED_NOTICES_PER_ROOM);
             for (const eventId of pinnedEventIds) {
                 const timeline = await this._matrixClient.getEventTimeline(room.getUnfilteredTimelineSet(), eventId);
-                const event = timeline.getEvents().find((ev) => ev.getId() === eventId);
+                const event = timeline?.getEvents().find((ev) => ev.getId() === eventId);
                 if (event) events.push(event);
             }
         }
@@ -390,7 +390,7 @@ class LoggedInView extends React.Component<IProps, IState> {
         if (inputableElement?.focus) {
             inputableElement.focus();
         } else {
-            const inThread = !!document.activeElement.closest(".mx_ThreadView");
+            const inThread = !!document.activeElement?.closest(".mx_ThreadView");
             // refocusing during a paste event will make the paste end up in the newly focused element,
             // so dispatch synchronously before paste happens
             dis.dispatch(
@@ -533,11 +533,11 @@ class LoggedInView extends React.Component<IProps, IState> {
                 });
                 break;
             case KeyBindingAction.PreviousVisitedRoomOrSpace:
-                PlatformPeg.get().navigateForwardBack(true);
+                PlatformPeg.get()?.navigateForwardBack(true);
                 handled = true;
                 break;
             case KeyBindingAction.NextVisitedRoomOrSpace:
-                PlatformPeg.get().navigateForwardBack(false);
+                PlatformPeg.get()?.navigateForwardBack(false);
                 handled = true;
                 break;
         }
@@ -555,7 +555,7 @@ class LoggedInView extends React.Component<IProps, IState> {
                     );
                     SettingsStore.setValue(
                         "showHiddenEventsInTimeline",
-                        undefined,
+                        null,
                         SettingLevel.DEVICE,
                         !hiddenEventVisibility,
                     );
@@ -567,7 +567,7 @@ class LoggedInView extends React.Component<IProps, IState> {
 
         if (
             !handled &&
-            PlatformPeg.get().overrideBrowserShortcuts() &&
+            PlatformPeg.get()?.overrideBrowserShortcuts() &&
             ev.code.startsWith("Digit") &&
             ev.code !== "Digit0" && // this is the shortcut for reset zoom, don't override it
             isOnlyCtrlOrCmdKeyEvent(ev)
@@ -599,7 +599,7 @@ class LoggedInView extends React.Component<IProps, IState> {
             // If the user is entering a printable character outside of an input field
             // redirect it to the composer for them.
             if (!isClickShortcut && isPrintable && !getInputableElement(ev.target as HTMLElement)) {
-                const inThread = !!document.activeElement.closest(".mx_ThreadView");
+                const inThread = !!document.activeElement?.closest(".mx_ThreadView");
                 // synchronous dispatch so we focus before key generates input
                 dis.dispatch(
                     {