finish up most of our helper classes. there are no lint issues in the

new classes. The CallViewModel is not done yet however

src/state/remoteMembers/displayname.ts

@@ -6,18 +6,12 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { type RoomMember, RoomStateEvent } from "matrix-js-sdk";
-import {
-  combineLatest,
-  fromEvent,
-  map,
-  type Observable,
-  startWith,
-} from "rxjs";
+import { combineLatest, fromEvent, type Observable, startWith } from "rxjs";
 import { type CallMembership } from "matrix-js-sdk/lib/matrixrtc";
 import { logger } from "matrix-js-sdk/lib/logger";
 import { type Room as MatrixRoom } from "matrix-js-sdk/lib/matrix";
 // eslint-disable-next-line rxjs/no-internal
-import { type HasEventTargetAddRemove } from "rxjs/internal/observable/fromEvent";
+import { type NodeStyleEventEmitter } from "rxjs/internal/observable/fromEvent";
 
 import { type ObservableScope } from "../ObservableScope";
 import {
@@ -36,20 +30,21 @@ import { type Behavior } from "../Behavior";
 // don't do this work more times than we need to. This is achieved by converting to a behavior:
 export const memberDisplaynames$ = (
   scope: ObservableScope,
-  matrixRoom: Pick<MatrixRoom, "getMember"> & HasEventTargetAddRemove<unknown>,
+  matrixRoom: Pick<MatrixRoom, "getMember"> & NodeStyleEventEmitter,
   memberships$: Observable<CallMembership[]>,
   userId: string,
   deviceId: string,
 ): Behavior<Map<string, string>> =>
   scope.behavior(
-    combineLatest([
-      // Handle call membership changes
-      memberships$,
-      // Additionally handle display name changes (implicitly reacting to them)
-      fromEvent(matrixRoom, RoomStateEvent.Members).pipe(startWith(null)),
-      // TODO: do we need: pauseWhen(this.pretendToBeDisconnected$),
-    ]).pipe(
-      map((memberships, _displaynames) => {
+    combineLatest(
+      [
+        // Handle call membership changes
+        memberships$,
+        // Additionally handle display name changes (implicitly reacting to them)
+        fromEvent(matrixRoom, RoomStateEvent.Members).pipe(startWith(null)),
+        // TODO: do we need: pauseWhen(this.pretendToBeDisconnected$),
+      ],
+      (memberships, _displaynames) => {
         const displaynameMap = new Map<string, string>([
           [
             `${userId}:${deviceId}`,
@@ -76,7 +71,7 @@ export const memberDisplaynames$ = (
           );
         }
         return displaynameMap;
-      }),
+      },
     ),
     new Map<string, string>(),
   );