Enable lint rules for Promise handling to discourage misuse of them. (#2607)

* Enable lint rules for Promise handling to discourage misuse of them.
Squashed all of Hugh's commits into one.

---------

Co-authored-by: Hugh Nimmo-Smith <hughns@element.io>

src/utils/matrix.ts

@@ -260,34 +260,40 @@ export async function createRoom(
   });
 
   // Wait for the room to arrive
-  await new Promise<void>((resolve, reject) => {
-    const onRoom = async (room: Room): Promise<void> => {
-      if (room.roomId === (await createPromise).room_id) {
-        resolve();
-        cleanUp();
-      }
-    };
+  const roomId = await new Promise<string>((resolve, reject) => {
     createPromise.catch((e) => {
       reject(e);
       cleanUp();
     });
 
+    const onRoom = (room: Room): void => {
+      createPromise.then(
+        (result) => {
+          if (room.roomId === result.room_id) {
+            resolve(room.roomId);
+            cleanUp();
+          }
+        },
+        (e) => {
+          logger.error("Failed to wait for the room to arrive", e);
+        },
+      );
+    };
+
     const cleanUp = (): void => {
       client.off(ClientEvent.Room, onRoom);
     };
     client.on(ClientEvent.Room, onRoom);
   });
 
-  const result = await createPromise;
-
-  let password;
+  let password: string | undefined;
   if (e2ee == E2eeType.SHARED_KEY) {
     password = secureRandomBase64Url(16);
-    saveKeyForRoom(result.room_id, password);
+    saveKeyForRoom(roomId, password);
   }
 
   return {
-    roomId: result.room_id,
+    roomId,
     alias: e2ee ? undefined : fullAliasFromRoomName(name, client),
     password,
   };

src/utils/media.ts

@@ -11,11 +11,11 @@ Please see LICENSE in the repository root for full details.
  * @param devices The list of devices to search
  * @returns A matching media device or undefined if no matching device was found
  */
-export async function findDeviceByName(
+export function findDeviceByName(
   deviceName: string,
   kind: MediaDeviceKind,
   devices: MediaDeviceInfo[],
-): Promise<string | undefined> {
+): string | undefined {
   const deviceInfo = devices.find(
     (d) => d.kind === kind && d.label === deviceName,
   );