Kill off enzyme in preference of react testing library (#10255)

src/components/views/emojipicker/EmojiPicker.tsx

@@ -186,7 +186,7 @@ class EmojiPicker extends React.Component<IProps, IState> {
     private onChangeFilter = (filter: string): void => {
         const lcFilter = filter.toLowerCase().trim(); // filter is case insensitive
         for (const cat of this.categories) {
-            let emojis;
+            let emojis: IEmoji[];
             // If the new filter string includes the old filter string, we don't have to re-filter the whole dataset.
             if (lcFilter.includes(this.state.filter)) {
                 emojis = this.memoizedDataByCategory[cat.id];

src/components/views/messages/MLocationBody.tsx

@@ -43,6 +43,8 @@ interface IState {
 export default class MLocationBody extends React.Component<IBodyProps, IState> {
     public static contextType = MatrixClientContext;
     public context!: React.ContextType<typeof MatrixClientContext>;
+
+    private unmounted = false;
     private mapId: string;
     private reconnectedListener: ClientEventHandlerMap[ClientEvent.Sync];
 
@@ -80,11 +82,15 @@ export default class MLocationBody extends React.Component<IBodyProps, IState> {
     };
 
     private onError = (error: Error): void => {
+        if (this.unmounted) return;
         this.setState({ error });
+        // Unregister first in case we already had it registered
+        this.context.off(ClientEvent.Sync, this.reconnectedListener);
         this.context.on(ClientEvent.Sync, this.reconnectedListener);
     };
 
     public componentWillUnmount(): void {
+        this.unmounted = true;
         this.context.off(ClientEvent.Sync, this.reconnectedListener);
     }