send receipt to server when clearing unread state so notif count clears

src/matrix/net/HomeServerApi.js

@@ -136,6 +136,11 @@ export class HomeServerApi {
         return this._put(`/rooms/${encodeURIComponent(roomId)}/send/${encodeURIComponent(eventType)}/${encodeURIComponent(txnId)}`, {}, content, options);
     }
 
+    receipt(roomId, receiptType, eventId, options = null) {
+        return this._post(`/rooms/${encodeURIComponent(roomId)}/receipt/${encodeURIComponent(receiptType)}/${encodeURIComponent(eventId)}`,
+            {}, {}, options);
+    }
+
     passwordLogin(username, password, options = null) {
         return this._post("/login", null, {
           "type": "m.login.password",

src/matrix/room/Room.js

@@ -201,8 +201,23 @@ export class Room extends EventEmitter {
         return this._summary.notificationCount;
     }
 
+    async _getLastEventId() {
+        const lastKey = this._syncWriter.lastMessageKey;
+        if (lastKey) {
+            const txn = await this._storage.readTxn([
+                this._storage.storeNames.timelineEvents,
+            ]);
+            const eventEntry = await txn.timelineEvents.get(this._roomId, lastKey);
+            return eventEntry?.event?.event_id;
+        }
+    }
+
     async clearUnread() {
-        if (this.isUnread) {
+        if (this.isUnread || this.notificationCount) {
+            const lastEventId = await this._getLastEventId();
+            if (lastEventId) {
+                await this._hsApi.receipt(this._roomId, "m.read", lastEventId);
+            }
             const txn = await this._storage.readWriteTxn([
                 this._storage.storeNames.roomSummary,
             ]);

src/matrix/room/timeline/persistence/SyncWriter.js

@@ -209,6 +209,10 @@ export class SyncWriter {
     afterSync(newLiveKey) {
         this._lastLiveKey = newLiveKey;
     }
+
+    get lastMessageKey() {
+        return this._lastLiveKey;
+    }
 }
 
 //import MemoryStorage from "../storage/memory/MemoryStorage.js";