diff --git a/src/components/views/rooms/WhoIsTypingTile.js b/src/components/views/rooms/WhoIsTypingTile.tsx
similarity index 76%
rename from src/components/views/rooms/WhoIsTypingTile.js
rename to src/components/views/rooms/WhoIsTypingTile.tsx
index a25b43fc3a..21afbc30f4 100644
--- a/src/components/views/rooms/WhoIsTypingTile.js
+++ b/src/components/views/rooms/WhoIsTypingTile.tsx
@@ -16,36 +16,44 @@ limitations under the License.
 */
 
 import React from 'react';
-import PropTypes from 'prop-types';
+import Room from "matrix-js-sdk/src/models/room";
+import { RoomMember } from "matrix-js-sdk/src/models/room-member";
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+
 import * as WhoIsTyping from '../../../WhoIsTyping';
 import Timer from '../../../utils/Timer';
-import {MatrixClientPeg} from '../../../MatrixClientPeg';
+import { MatrixClientPeg } from '../../../MatrixClientPeg';
 import MemberAvatar from '../avatars/MemberAvatar';
-import {replaceableComponent} from "../../../utils/replaceableComponent";
+import { replaceableComponent } from "../../../utils/replaceableComponent";
+
+interface IProps {
+    // the room this statusbar is representing.
+    room: Room;
+    onShown?: () => void;
+    onHidden?: () => void;
+    // Number of names to display in typing indication. E.g. set to 3, will
+    // result in "X, Y, Z and 100 others are typing."
+    whoIsTypingLimit: number;
+}
+
+interface IState {
+    usersTyping: RoomMember[];
+    // a map with userid => Timer to delay
+    // hiding the "x is typing" message for a
+    // user so hiding it can coincide
+    // with the sent message by the other side
+    // resulting in less timeline jumpiness
+    delayedStopTypingTimers: Record<string, Timer>;
+}
 
 @replaceableComponent("views.rooms.WhoIsTypingTile")
-export default class WhoIsTypingTile extends React.Component {
-    static propTypes = {
-        // the room this statusbar is representing.
-        room: PropTypes.object.isRequired,
-        onShown: PropTypes.func,
-        onHidden: PropTypes.func,
-        // Number of names to display in typing indication. E.g. set to 3, will
-        // result in "X, Y, Z and 100 others are typing."
-        whoIsTypingLimit: PropTypes.number,
-    };
-
+export default class WhoIsTypingTile extends React.Component<IProps, IState> {
     static defaultProps = {
         whoIsTypingLimit: 3,
     };
 
     state = {
         usersTyping: WhoIsTyping.usersTypingApartFromMe(this.props.room),
-        // a map with userid => Timer to delay
-        // hiding the "x is typing" message for a
-        // user so hiding it can coincide
-        // with the sent message by the other side
-        // resulting in less timeline jumpiness
         delayedStopTypingTimers: {},
     };
 
@@ -71,37 +79,39 @@ export default class WhoIsTypingTile extends React.Component {
             client.removeListener("RoomMember.typing", this.onRoomMemberTyping);
             client.removeListener("Room.timeline", this.onRoomTimeline);
         }
-        Object.values(this.state.delayedStopTypingTimers).forEach((t) => t.abort());
+        Object.values(this.state.delayedStopTypingTimers).forEach((t) => (t as Timer).abort());
     }
 
-    _isVisible(state) {
+    private _isVisible(state: IState): boolean {
         return state.usersTyping.length !== 0 || Object.keys(state.delayedStopTypingTimers).length !== 0;
     }
 
-    isVisible = () => {
+    public isVisible = (): boolean => {
         return this._isVisible(this.state);
     };
 
-    onRoomTimeline = (event, room) => {
+    private onRoomTimeline = (event: MatrixEvent, room: Room): void => {
         if (room?.roomId === this.props.room?.roomId) {
             const userId = event.getSender();
             // remove user from usersTyping
             const usersTyping = this.state.usersTyping.filter((m) => m.userId !== userId);
-            this.setState({usersTyping});
+            if (usersTyping.length !== this.state.usersTyping.length) {
+                this.setState({usersTyping});
+            }
             // abort timer if any
-            this._abortUserTimer(userId);
+            this.abortUserTimer(userId);
         }
     };
 
-    onRoomMemberTyping = (ev, member) => {
+    private onRoomMemberTyping = (): void => {
         const usersTyping = WhoIsTyping.usersTypingApartFromMeAndIgnored(this.props.room);
         this.setState({
-            delayedStopTypingTimers: this._updateDelayedStopTypingTimers(usersTyping),
+            delayedStopTypingTimers: this.updateDelayedStopTypingTimers(usersTyping),
             usersTyping,
         });
     };
 
-    _updateDelayedStopTypingTimers(usersTyping) {
+    private updateDelayedStopTypingTimers(usersTyping: RoomMember[]): Record<string, Timer> {
         const usersThatStoppedTyping = this.state.usersTyping.filter((a) => {
             return !usersTyping.some((b) => a.userId === b.userId);
         });
@@ -129,7 +139,7 @@ export default class WhoIsTypingTile extends React.Component {
                 delayedStopTypingTimers[m.userId] = timer;
                 timer.start();
                 timer.finished().then(
-                    () => this._removeUserTimer(m.userId), // on elapsed
+                    () => this.removeUserTimer(m.userId), // on elapsed
                     () => {/* aborted */},
                 );
             }
@@ -139,15 +149,15 @@ export default class WhoIsTypingTile extends React.Component {
         return delayedStopTypingTimers;
     }
 
-    _abortUserTimer(userId) {
+    private abortUserTimer(userId: string): void {
         const timer = this.state.delayedStopTypingTimers[userId];
         if (timer) {
             timer.abort();
-            this._removeUserTimer(userId);
+            this.removeUserTimer(userId);
         }
     }
 
-    _removeUserTimer(userId) {
+    private removeUserTimer(userId: string): void {
         const timer = this.state.delayedStopTypingTimers[userId];
         if (timer) {
             const delayedStopTypingTimers = Object.assign({}, this.state.delayedStopTypingTimers);
@@ -156,7 +166,7 @@ export default class WhoIsTypingTile extends React.Component {
         }
     }
 
-    _renderTypingIndicatorAvatars(users, limit) {
+    private renderTypingIndicatorAvatars(users: RoomMember[], limit: number): JSX.Element[] {
         let othersCount = 0;
         if (users.length > limit) {
             othersCount = users.length - limit + 1;
@@ -210,7 +220,7 @@ export default class WhoIsTypingTile extends React.Component {
         return (
             <li className="mx_WhoIsTypingTile" aria-atomic="true">
                 <div className="mx_WhoIsTypingTile_avatars">
-                    { this._renderTypingIndicatorAvatars(usersTyping, this.props.whoIsTypingLimit) }
+                    { this.renderTypingIndicatorAvatars(usersTyping, this.props.whoIsTypingLimit) }
                 </div>
                 <div className="mx_WhoIsTypingTile_label">
                     { typingString }