very basic support for lazy loading

src/matrix/hs-api.js

@@ -48,7 +48,12 @@ export default class HomeServerApi {
     _request(method, csPath, queryParams = {}, body) {
         const queryString = Object.entries(queryParams)
             .filter(([, value]) => value !== undefined)
-            .map(([name, value]) => `${encodeURIComponent(name)}=${encodeURIComponent(value)}`)
+            .map(([name, value]) => {
+                if (typeof value === "object") {
+                    value = JSON.stringify(value);
+                }
+                return `${encodeURIComponent(name)}=${encodeURIComponent(value)}`;
+            })
             .join("&");
         const url = this._url(`${csPath}?${queryString}`);
         let bodyString;
@@ -117,11 +122,11 @@ export default class HomeServerApi {
 
     // params is from, dir and optionally to, limit, filter.
     messages(roomId, params) {
-        return this._get(`/rooms/${roomId}/messages`, params);
+        return this._get(`/rooms/${encodeURIComponent(roomId)}/messages`, params);
     }
 
     send(roomId, eventType, txnId, content) {
-        return this._put(`/rooms/${roomId}/send/${eventType}/${txnId}`, {}, content);
+        return this._put(`/rooms/${encodeURIComponent(roomId)}/send/${encodeURIComponent(eventType)}/${encodeURIComponent(txnId)}`, {}, content);
     }
 
     passwordLogin(username, password) {
@@ -134,4 +139,8 @@ export default class HomeServerApi {
           "password": password
         });
     }
+
+    createFilter(userId, filter) {
+        return this._post(`/user/${encodeURIComponent(userId)}/filter`, undefined, filter);
+    }
 }

src/matrix/room/timeline/Timeline.js

@@ -41,7 +41,8 @@ export default class Timeline {
         const response = await this._hsApi.messages(this._roomId, {
             from: fragmentEntry.token,
             dir: fragmentEntry.direction.asApiString(),
-            limit: amount
+            limit: amount,
+            filter: {lazy_load_members: true}
         }).response();
         const gapWriter = new GapWriter({
             roomId: this._roomId,

src/matrix/session.js

@@ -77,9 +77,10 @@ export default class Session {
         return room;
     }
 
-    persistSync(syncToken, accountData, txn) {
+    persistSync(syncToken, syncFilterId, accountData, txn) {
         if (syncToken !== this._session.syncToken) {
             this._session.syncToken = syncToken;
+            this._session.syncFilterId = syncFilterId;
             txn.session.set(this._session);
         }
     }
@@ -88,6 +89,10 @@ export default class Session {
         return this._session.syncToken;
     }
 
+    get syncFilterId() {
+        return this._session.syncFilterId;
+    }
+
     get user() {
         return this._user;
     }

src/matrix/sync.js

@@ -67,7 +67,11 @@ export default class Sync extends EventEmitter {
     }
 
     async _syncRequest(syncToken, timeout) {
-        this._currentRequest = this._hsApi.sync(syncToken, undefined, timeout);
+        let {syncFilterId} = this._session;
+        if (typeof syncFilterId !== "string") {
+            syncFilterId = (await this._hsApi.createFilter(this._session.user.id, {room: {state: {lazy_load_members: true}}}).response()).filter_id;
+        }
+        this._currentRequest = this._hsApi.sync(syncToken, syncFilterId, timeout);
         const response = await this._currentRequest.response();
         syncToken = response.next_batch;
         const storeNames = this._storage.storeNames;
@@ -81,7 +85,7 @@ export default class Sync extends EventEmitter {
         ]);
         const roomChanges = [];
         try {
-            this._session.persistSync(syncToken, response.account_data, syncTxn);
+            this._session.persistSync(syncToken, syncFilterId, response.account_data,  syncTxn);
             // to_device
             // presence
             if (response.rooms) {