Conform more of the codebase to strictNullChecks (#11134)

src/components/structures/RoomView.tsx

@@ -1704,7 +1704,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
         } catch (error) {
             logger.error(`Failed to reject invite: ${error}`);
 
-            const msg = error.message ? error.message : JSON.stringify(error);
+            const msg = error instanceof Error ? error.message : JSON.stringify(error);
             Modal.createDialog(ErrorDialog, {
                 title: _t("Failed to reject invite"),
                 description: msg,

src/components/structures/ScrollPanel.tsx

@@ -700,7 +700,7 @@ export default class ScrollPanel extends React.Component<IProps> {
             const trackedNode = this.getTrackedNode();
             if (trackedNode) {
                 const newBottomOffset = this.topFromBottom(trackedNode);
-                const bottomDiff = newBottomOffset - scrollState.bottomOffset;
+                const bottomDiff = newBottomOffset - (scrollState.bottomOffset ?? 0);
                 this.bottomGrowth += bottomDiff;
                 scrollState.bottomOffset = newBottomOffset;
                 const newHeight = `${this.getListHeight()}px`;

src/components/structures/TimelinePanel.tsx

@@ -599,7 +599,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
 
         if (!this.timelineWindow?.canPaginate(dir)) {
             debuglog("can't", dir, "paginate any further");
-            this.setState<null>({ [canPaginateKey]: false });
+            this.setState({ [canPaginateKey]: false } as Pick<IState, typeof canPaginateKey>);
             return Promise.resolve(false);
         }
 
@@ -609,7 +609,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
         }
 
         debuglog("Initiating paginate; backwards:" + backwards);
-        this.setState<null>({ [paginatingKey]: true });
+        this.setState({ [paginatingKey]: true } as Pick<IState, typeof paginatingKey>);
 
         return this.onPaginationRequest(this.timelineWindow, dir, PAGINATE_SIZE).then(async (r) => {
             if (this.unmounted) {
@@ -2012,7 +2012,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
         return receiptStore?.getEventReadUpTo(myUserId, ignoreSynthesized) ?? null;
     }
 
-    private setReadMarker(eventId: string | null, eventTs: number, inhibitSetState = false): void {
+    private setReadMarker(eventId: string | null, eventTs?: number, inhibitSetState = false): void {
         const roomId = this.props.timelineSet.room?.roomId;
 
         // don't update the state (and cause a re-render) if there is
@@ -2023,7 +2023,11 @@ class TimelinePanel extends React.Component<IProps, IState> {
 
         // in order to later figure out if the read marker is
         // above or below the visible timeline, we stash the timestamp.
-        TimelinePanel.roomReadMarkerTsMap[roomId ?? ""] = eventTs;
+        if (eventTs !== undefined) {
+            TimelinePanel.roomReadMarkerTsMap[roomId ?? ""] = eventTs;
+        } else {
+            delete TimelinePanel.roomReadMarkerTsMap[roomId ?? ""];
+        }
 
         if (inhibitSetState) {
             return;

src/components/views/messages/MjolnirBody.tsx

@@ -18,7 +18,7 @@ import React from "react";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 
 import { _t } from "../../../languageHandler";
-import AccessibleButton from "../elements/AccessibleButton";
+import AccessibleButton, { ButtonEvent } from "../elements/AccessibleButton";
 
 interface IProps {
     mxEvent: MatrixEvent;
@@ -26,7 +26,7 @@ interface IProps {
 }
 
 export default class MjolnirBody extends React.Component<IProps> {
-    private onAllowClick = (e: React.MouseEvent): void => {
+    private onAllowClick = (e: ButtonEvent): void => {
         e.preventDefault();
         e.stopPropagation();
 

src/components/views/rooms/RoomListHeader.tsx

@@ -171,7 +171,7 @@ const RoomListHeader: React.FC<IProps> = ({ onVisibilityChange }) => {
         contextMenu = (
             <ContextMenuComponent
                 {...contextMenuBelow(mainMenuHandle.current.getBoundingClientRect())}
-                space={activeSpace}
+                space={activeSpace!}
                 onFinished={closeMainMenu}
                 hideHeader={true}
             />

src/components/views/rooms/RoomPreviewBar.tsx

@@ -155,7 +155,7 @@ export default class RoomPreviewBar extends React.Component<IProps, IState> {
                 );
                 this.setState({ invitedEmailMxid: result.mxid });
             } catch (err) {
-                this.setState({ threePidFetchError: err });
+                this.setState({ threePidFetchError: err as MatrixError });
             }
             this.setState({ busy: false });
         }