feat: LiveQueryClient.close returns promise when WebSocket closes (#1735)

Author: dplewis

integration/test/ParseLiveQueryTest.js

@@ -9,6 +9,12 @@ describe('Parse LiveQuery', () => {
     Parse.User.enableUnsafeCurrentUser();
   });
 
+  afterEach(async () => {
+    const client = await Parse.CoreManager.getLiveQueryController().getDefaultLiveQueryClient();
+    client.state = 'closed';
+    await client.close();
+  });
+
   it('can subscribe to query', async done => {
     const object = new TestObject();
     await object.save();
@@ -66,9 +72,9 @@ describe('Parse LiveQuery', () => {
     const query = new Parse.Query(TestObject);
     query.equalTo('objectId', object.id);
     const subscription = await client.subscribe(query);
-    subscription.on('update', async object => {
+    subscription.on('update', async (object) => {
       assert.equal(object.get('foo'), 'bar');
-      client.close();
+      await client.close();
       done();
     });
     await subscription.subscribePromise;
@@ -279,7 +285,8 @@ describe('Parse LiveQuery', () => {
     await expectAsync(subscription.subscribePromise).toBeRejectedWith(
       new Parse.Error(141, 'not allowed to subscribe')
     );
-    client.close();
+    client.state = 'closed';
+    await client.close();
   });
 
   it('connectPromise does throw', async () => {
@@ -306,6 +313,7 @@ describe('Parse LiveQuery', () => {
     await expectAsync(subscription.subscribePromise).toBeRejectedWith(
       new Parse.Error(141, 'not allowed to connect')
     );
-    client.close();
+    client.state = 'closed';
+    await client.close();
   });
 });

src/LiveQueryClient.js

@@ -258,6 +258,7 @@ class LiveQueryClient extends EventEmitter {
     }
 
     this.socket = new WebSocketImplementation(this.serverURL);
+    this.socket.closingPromise = resolvingPromise();
 
     // Bind WebSocket callbacks
     this.socket.onopen = () => {
@@ -268,7 +269,8 @@ class LiveQueryClient extends EventEmitter {
       this._handleWebSocketMessage(event);
     };
 
-    this.socket.onclose = () => {
+    this.socket.onclose = (event) => {
+      this.socket.closingPromise.resolve(event);
       this._handleWebSocketClose();
     };
 
@@ -309,20 +311,22 @@ class LiveQueryClient extends EventEmitter {
    * This method will close the WebSocket connection to this LiveQueryClient,
    * cancel the auto reconnect and unsubscribe all subscriptions based on it.
    *
+   * @returns {Promise | undefined} CloseEvent {@link https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/close_event}
    */
-  close() {
+  close(): ?Promise {
     if (this.state === CLIENT_STATE.INITIALIZED || this.state === CLIENT_STATE.DISCONNECTED) {
       return;
     }
     this.state = CLIENT_STATE.DISCONNECTED;
-    this.socket.close();
+    this.socket?.close();
     // Notify each subscription about the close
     for (const subscription of this.subscriptions.values()) {
       subscription.subscribed = false;
       subscription.emit(SUBSCRIPTION_EMMITER_TYPES.CLOSE);
     }
     this._handleReset();
     this.emit(CLIENT_EMMITER_TYPES.CLOSE);
+    return this.socket?.closingPromise;
   }
 
   // ensure we start with valid state if connect is called again after close

src/Socket.weapp.js

@@ -13,8 +13,8 @@ module.exports = class SocketWeapp {
       this.onmessage(msg);
     });
 
-    wx.onSocketClose(() => {
-      this.onclose();
+    wx.onSocketClose((event) => {
+      this.onclose(event);
     });
 
     wx.onSocketError(error => {