Conform more of the codebase to strictNullChecks

src/autocomplete/Autocompleter.ts

@@ -39,7 +39,7 @@ export interface ICompletion {
     type?: "at-room" | "command" | "community" | "room" | "user";
     completion: string;
     completionId?: string;
-    component?: ReactElement;
+    component: ReactElement;
     range: ISelectionRange;
     command?: string;
     suffix?: string;

src/components/structures/LoggedInView.tsx

@@ -231,7 +231,7 @@ class LoggedInView extends React.Component<IProps, IState> {
     };
 
     private createResizer(): Resizer {
-        let panelSize: number;
+        let panelSize: number | null;
         let panelCollapsed: boolean;
         const collapseConfig: ICollapseConfig = {
             // TODO decrease this once Spaces launches as it'll no longer need to include the 56px Community Panel

src/components/views/avatars/RoomAvatar.tsx

@@ -110,6 +110,7 @@ export default class RoomAvatar extends React.Component<IProps, IState> {
 
     private onRoomAvatarClick = (): void => {
         const avatarUrl = Avatar.avatarUrlForRoom(this.props.room ?? null, undefined, undefined, undefined);
+        if (!avatarUrl) return;
         const params = {
             src: avatarUrl,
             name: this.props.room?.name,

src/components/views/dialogs/CreateSubspaceDialog.tsx

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { RefObject, useRef, useState } from "react";
+import React, { useRef, useState } from "react";
 import { Room } from "matrix-js-sdk/src/models/room";
 import { JoinRule } from "matrix-js-sdk/src/@types/partials";
 import { logger } from "matrix-js-sdk/src/logger";
@@ -41,9 +41,9 @@ const CreateSubspaceDialog: React.FC<IProps> = ({ space, onAddExistingSpaceClick
 
     const [busy, setBusy] = useState<boolean>(false);
     const [name, setName] = useState("");
-    const spaceNameField = useRef() as RefObject<Field>;
+    const spaceNameField = useRef<Field>(null);
     const [alias, setAlias] = useState("");
-    const spaceAliasField = useRef() as RefObject<RoomAliasField>;
+    const spaceAliasField = useRef<RoomAliasField>(null);
     const [avatar, setAvatar] = useState<File | undefined>();
     const [topic, setTopic] = useState<string>("");
 

src/components/views/dialogs/ExportDialog.tsx

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { useRef, useState, Dispatch, SetStateAction, RefObject } from "react";
+import React, { useRef, useState, Dispatch, SetStateAction } from "react";
 import { Room } from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
 
@@ -104,8 +104,8 @@ const ExportDialog: React.FC<IProps> = ({ room, onFinished }) => {
     } = useExportFormState();
 
     const [isExporting, setExporting] = useState(false);
-    const sizeLimitRef = useRef() as RefObject<Field>;
-    const messageCountRef = useRef() as RefObject<Field>;
+    const sizeLimitRef = useRef<Field>(null);
+    const messageCountRef = useRef<Field>(null);
     const [exportProgressText, setExportProgressText] = useState(_t("Processing…"));
     const [displayCancel, setCancelWarning] = useState(false);
     const [exportCancelled, setExportCancelled] = useState(false);

src/components/views/dialogs/RegistrationEmailPromptDialog.tsx

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import * as React from "react";
-import { RefObject, SyntheticEvent, useRef, useState } from "react";
+import { SyntheticEvent, useRef, useState } from "react";
 
 import { _t, _td } from "../../../languageHandler";
 import Field from "../elements/Field";
@@ -30,7 +30,7 @@ interface IProps {
 
 const RegistrationEmailPromptDialog: React.FC<IProps> = ({ onFinished }) => {
     const [email, setEmail] = useState("");
-    const fieldRef = useRef() as RefObject<Field>;
+    const fieldRef = useRef<Field>(null);
 
     const onSubmit = async (e: SyntheticEvent): Promise<void> => {
         e.preventDefault();

src/components/views/dialogs/ReportEventDialog.tsx

@@ -255,7 +255,7 @@ export default class ReportEventDialog extends React.Component<IProps, IState> {
                 });
             } else {
                 // Report to homeserver admin through the dedicated Matrix API.
-                await client.reportEvent(ev.getRoomId(), ev.getId(), -100, this.state.reason.trim());
+                await client.reportEvent(ev.getRoomId()!, ev.getId()!, -100, this.state.reason.trim());
             }
 
             // if the user should also be ignored, do that
@@ -340,7 +340,7 @@ export default class ReportEventDialog extends React.Component<IProps, IState> {
                     );
                     break;
                 case NonStandardValue.Admin:
-                    if (client.isRoomEncrypted(this.props.mxEvent.getRoomId())) {
+                    if (client.isRoomEncrypted(this.props.mxEvent.getRoomId()!)) {
                         subtitle = _t(
                             "This room is dedicated to illegal or toxic content " +
                                 "or the moderators fail to moderate illegal or toxic content.\n" +

src/components/views/dialogs/spotlight/SpotlightDialog.tsx

@@ -288,8 +288,8 @@ interface IDirectoryOpts {
 }
 
 const SpotlightDialog: React.FC<IProps> = ({ initialText = "", initialFilter = null, onFinished }) => {
-    const inputRef = useRef() as RefObject<HTMLInputElement>;
-    const scrollContainerRef = useRef() as RefObject<HTMLDivElement>;
+    const inputRef = useRef<HTMLInputElement>(null);
+    const scrollContainerRef = useRef<HTMLDivElement>(null);
     const cli = MatrixClientPeg.get();
     const rovingContext = useContext(RovingTabIndexContext);
     const [query, _setQuery] = useState(initialText);

src/components/views/elements/MiniAvatarUploader.tsx

@@ -16,7 +16,7 @@ limitations under the License.
 
 import classNames from "classnames";
 import { EventType } from "matrix-js-sdk/src/@types/event";
-import React, { useContext, useRef, useState, MouseEvent, ReactNode, RefObject } from "react";
+import React, { useContext, useRef, useState, MouseEvent, ReactNode } from "react";
 
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import RoomContext from "../../../contexts/RoomContext";
@@ -59,7 +59,7 @@ const MiniAvatarUploader: React.FC<IProps> = ({
         setShow(false);
     }, 13000); // hide after being shown for 10 seconds
 
-    const uploadRef = useRef() as RefObject<HTMLInputElement>;
+    const uploadRef = useRef<HTMLInputElement>(null);
 
     const label = hasAvatar || busy ? hasAvatarLabel : noAvatarLabel;
 

src/components/views/elements/RoomTopic.tsx

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { RefObject, useCallback, useContext, useRef } from "react";
+import React, { useCallback, useContext, useRef } from "react";
 import { Room } from "matrix-js-sdk/src/models/room";
 import classNames from "classnames";
 import { EventType } from "matrix-js-sdk/src/@types/event";
@@ -38,7 +38,7 @@ interface IProps extends React.HTMLProps<HTMLDivElement> {
 
 export default function RoomTopic({ room, ...props }: IProps): JSX.Element {
     const client = useContext(MatrixClientContext);
-    const ref = useRef() as RefObject<HTMLDivElement>;
+    const ref = useRef<HTMLDivElement>(null);
 
     const topic = useTopic(room);
     const body = topicToHtml(topic?.text, topic?.html, ref);

src/components/views/right_panel/UserInfo.tsx

@@ -1504,9 +1504,10 @@ export const UserInfoHeader: React.FC<{
         const avatarUrl = (member as RoomMember).getMxcAvatarUrl
             ? (member as RoomMember).getMxcAvatarUrl()
             : (member as User).avatarUrl;
-        if (!avatarUrl) return;
 
         const httpUrl = mediaFromMxc(avatarUrl).srcHttp;
+        if (!httpUrl) return;
+
         const params = {
             src: httpUrl,
             name: (member as RoomMember).name || (member as User).displayName,

src/components/views/rooms/AuxPanel.tsx

@@ -100,14 +100,14 @@ export default class AuxPanel extends React.Component<IProps, IState> {
 
         if (this.props.room && SettingsStore.getValue("feature_state_counters")) {
             const stateEvs = this.props.room.currentState.getStateEvents("re.jki.counter");
-            stateEvs.sort((a, b) => lexicographicCompare(a.getStateKey(), b.getStateKey()));
+            stateEvs.sort((a, b) => lexicographicCompare(a.getStateKey()!, b.getStateKey()!));
 
             for (const ev of stateEvs) {
                 const title = ev.getContent().title;
                 const value = ev.getContent().value;
                 const link = ev.getContent().link;
                 const severity = ev.getContent().severity || "normal";
-                const stateKey = ev.getStateKey();
+                const stateKey = ev.getStateKey()!;
 
                 // We want a non-empty title but can accept falsy values (e.g.
                 // zero)

src/components/views/rooms/BasicMessageComposer.tsx

@@ -765,7 +765,7 @@ export default class BasicMessageEditor extends React.Component<IProps, IState>
 
     public render(): React.ReactNode {
         let autoComplete: JSX.Element | undefined;
-        if (this.state.autoComplete) {
+        if (this.state.autoComplete && this.state.query) {
             const query = this.state.query;
             const queryLen = query.length;
             autoComplete = (
@@ -800,8 +800,8 @@ export default class BasicMessageEditor extends React.Component<IProps, IState>
         const { completionIndex } = this.state;
         const hasAutocomplete = Boolean(this.state.autoComplete);
         let activeDescendant: string | undefined;
-        if (hasAutocomplete && completionIndex >= 0) {
-            activeDescendant = generateCompletionDomId(completionIndex);
+        if (hasAutocomplete && completionIndex! >= 0) {
+            activeDescendant = generateCompletionDomId(completionIndex!);
         }
 
         return (

src/components/views/rooms/EditMessageComposer.tsx

@@ -229,11 +229,11 @@ class EditMessageComposer extends React.Component<IEditMessageComposerProps, ISt
     }
 
     private get editorRoomKey(): string {
-        return editorRoomKey(this.props.editState.getEvent().getRoomId(), this.context.timelineRenderingType);
+        return editorRoomKey(this.props.editState.getEvent().getRoomId()!, this.context.timelineRenderingType);
     }
 
     private get editorStateKey(): string {
-        return editorStateKey(this.props.editState.getEvent().getId());
+        return editorStateKey(this.props.editState.getEvent().getId()!);
     }
 
     private get events(): MatrixEvent[] {
@@ -275,7 +275,7 @@ class EditMessageComposer extends React.Component<IEditMessageComposerProps, ISt
     private saveStoredEditorState = (): void => {
         const item = SendHistoryManager.createItem(this.model);
         this.clearPreviousEdit();
-        localStorage.setItem(this.editorRoomKey, this.props.editState.getEvent().getId());
+        localStorage.setItem(this.editorRoomKey, this.props.editState.getEvent().getId()!);
         localStorage.setItem(this.editorStateKey, JSON.stringify(item));
     };
 
@@ -329,7 +329,7 @@ class EditMessageComposer extends React.Component<IEditMessageComposerProps, ISt
 
         // If content is modified then send an updated event into the room
         if (this.isContentModified(newContent)) {
-            const roomId = editedEvent.getRoomId();
+            const roomId = editedEvent.getRoomId()!;
             if (!containsEmote(this.model) && isSlashCommand(this.model)) {
                 const [cmd, args, commandText] = getSlashCommand(this.model);
                 if (cmd) {

src/components/views/rooms/LinkPreviewWidget.tsx

@@ -43,11 +43,13 @@ export default class LinkPreviewWidget extends React.Component<IProps> {
         if (ev.button != 0 || ev.metaKey) return;
         ev.preventDefault();
 
-        let src = p["og:image"];
+        let src: string | null | undefined = p["og:image"];
         if (src?.startsWith("mxc://")) {
             src = mediaFromMxc(src).srcHttp;
         }
 
+        if (!src) return;
+
         const params: Omit<ComponentProps<typeof ImageView>, "onFinished"> = {
             src: src,
             width: p["og:image:width"],

src/components/views/rooms/MessageComposerButtons.tsx

@@ -17,7 +17,7 @@ limitations under the License.
 import classNames from "classnames";
 import { IEventRelation } from "matrix-js-sdk/src/models/event";
 import { M_POLL_START } from "matrix-js-sdk/src/@types/polls";
-import React, { createContext, MouseEventHandler, ReactElement, ReactNode, RefObject, useContext, useRef } from "react";
+import React, { createContext, MouseEventHandler, ReactElement, ReactNode, useContext, useRef } from "react";
 import { Room } from "matrix-js-sdk/src/models/room";
 import { MatrixClient } from "matrix-js-sdk/src/client";
 import { THREAD_RELATION_TYPE } from "matrix-js-sdk/src/models/thread";
@@ -180,7 +180,7 @@ interface IUploadButtonProps {
 const UploadButtonContextProvider: React.FC<IUploadButtonProps> = ({ roomId, relation, children }) => {
     const cli = useContext(MatrixClientContext);
     const roomContext = useContext(RoomContext);
-    const uploadInput = useRef() as RefObject<HTMLInputElement>;
+    const uploadInput = useRef<HTMLInputElement>(null);
 
     const onUploadClick = (): void => {
         if (cli?.isGuest()) {

src/components/views/rooms/ReadReceiptGroup.tsx

@@ -293,7 +293,7 @@ interface ISectionHeaderProps {
 }
 
 function SectionHeader({ className, children }: PropsWithChildren<ISectionHeaderProps>): JSX.Element {
-    const ref = useRef<HTMLHeadingElement>();
+    const ref = useRef<HTMLHeadingElement>(null);
     const [onFocus] = useRovingTabIndex(ref);
 
     return (

src/components/views/rooms/ReadReceiptMarker.tsx

@@ -124,7 +124,7 @@ export default class ReadReceiptMarker extends React.PureComponent<IProps, IStat
     private buildReadReceiptInfo(target: IReadReceiptInfo = {}): IReadReceiptInfo {
         const element = this.avatar.current;
         // this is the mx_ReadReceiptsGroup_container
-        const horizontalContainer = element.offsetParent;
+        const horizontalContainer = element?.offsetParent;
         if (!horizontalContainer || !(horizontalContainer instanceof HTMLElement)) {
             // this seems to happen sometimes for reasons I don't understand
             // the docs for `offsetParent` say it may be null if `display` is

src/components/views/rooms/RecentlyViewedButton.tsx

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { RefObject, useRef } from "react";
+import React, { useRef } from "react";
 
 import { BreadcrumbsStore } from "../../../stores/BreadcrumbsStore";
 import { UPDATE_EVENT } from "../../../stores/AsyncStore";
@@ -30,7 +30,7 @@ import { ViewRoomPayload } from "../../../dispatcher/payloads/ViewRoomPayload";
 import RoomAvatar from "../avatars/RoomAvatar";
 
 const RecentlyViewedButton: React.FC = () => {
-    const tooltipRef = useRef() as RefObject<InteractiveTooltip>;
+    const tooltipRef = useRef<InteractiveTooltip>(null);
     const crumbs = useEventEmitterState(BreadcrumbsStore.instance, UPDATE_EVENT, () => BreadcrumbsStore.instance.rooms);
 
     const content = (

src/components/views/rooms/ReplyTile.tsx

@@ -134,7 +134,7 @@ export default class ReplyTile extends React.PureComponent<IProps> {
 
         let permalink = "#";
         if (this.props.permalinkCreator) {
-            permalink = this.props.permalinkCreator.forEvent(mxEvent.getId());
+            permalink = this.props.permalinkCreator.forEvent(mxEvent.getId()!);
         }
 
         let sender;

src/components/views/spaces/SpaceBasicSettings.tsx

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { ChangeEvent, RefObject, useRef, useState } from "react";
+import React, { ChangeEvent, useRef, useState } from "react";
 
 import { _t } from "../../../languageHandler";
 import AccessibleButton from "../elements/AccessibleButton";
@@ -38,7 +38,7 @@ export const SpaceAvatar: React.FC<Pick<IProps, "avatarUrl" | "avatarDisabled" |
     avatarDisabled = false,
     setAvatar,
 }) => {
-    const avatarUploadRef = useRef() as RefObject<HTMLInputElement>;
+    const avatarUploadRef = useRef<HTMLInputElement>(null);
     const [avatar, setAvatarDataUrl] = useState(avatarUrl); // avatar data url cache
 
     let avatarSection;

src/customisations/Media.ts

@@ -77,7 +77,7 @@ export class Media {
      */
     public get srcHttp(): string | null {
         // eslint-disable-next-line no-restricted-properties
-        return this.client.mxcUrlToHttp(this.srcMxc);
+        return this.client.mxcUrlToHttp(this.srcMxc) || null;
     }
 
     /**

src/resizer/resizer.ts

@@ -44,7 +44,7 @@ export default class Resizer<C extends IConfig = IConfig> {
     // TODO move vertical/horizontal to config option/container class
     // as it doesn't make sense to mix them within one container/Resizer
     public constructor(
-        public container: HTMLElement,
+        public container: HTMLElement | null,
         private readonly distributorCtor: {
             new (item: ResizeItem): FixedDistributor<C, any>;
             createItem(
@@ -53,7 +53,7 @@ export default class Resizer<C extends IConfig = IConfig> {
                 sizer: Sizer,
                 container?: HTMLElement,
             ): ResizeItem;
-            createSizer(containerElement: HTMLElement, vertical: boolean, reverse: boolean): Sizer;
+            createSizer(containerElement: HTMLElement | null, vertical: boolean, reverse: boolean): Sizer;
         },
         public readonly config?: C,
     ) {
@@ -71,13 +71,13 @@ export default class Resizer<C extends IConfig = IConfig> {
 
     public attach(): void {
         const attachment = this?.config?.handler?.parentElement ?? this.container;
-        attachment.addEventListener("mousedown", this.onMouseDown, false);
+        attachment?.addEventListener("mousedown", this.onMouseDown, false);
         window.addEventListener("resize", this.onResize);
     }
 
     public detach(): void {
         const attachment = this?.config?.handler?.parentElement ?? this.container;
-        attachment.removeEventListener("mousedown", this.onMouseDown, false);
+        attachment?.removeEventListener("mousedown", this.onMouseDown, false);
         window.removeEventListener("resize", this.onResize);
     }
 
@@ -194,7 +194,7 @@ export default class Resizer<C extends IConfig = IConfig> {
         const Distributor = this.distributorCtor;
         const useItemContainer = this.config?.handler ? this.container : undefined;
         const sizer = Distributor.createSizer(this.container, vertical, reverse);
-        const item = Distributor.createItem(resizeHandle, this, sizer, useItemContainer);
+        const item = Distributor.createItem(resizeHandle, this, sizer, useItemContainer ?? undefined);
         const distributor = new Distributor(item);
         return { sizer, distributor };
     }