afterLiveQueryEvent Triggers

_includes/cloudcode/cloud-code.md

@@ -636,6 +636,64 @@ Parse.Cloud.beforeSubscribe('MyObject', request => {
 });
 ```
 
+## afterLiveQueryEvent
+
+*Available only on parse-server cloud code starting 4.-.-*
+
+In some cases you may want to manipulate the results of a Live Query before they are sent to the client. You can do so with the `afterLiveQueryEvent` trigger.
+
+### Examples
+
+```javascript
+// Changing values on object and original
+Parse.Cloud.afterLiveQueryEvent('MyObject', request => {
+  const object = request.object;
+  object.set('name', '***');
+
+  const original = request.original;
+  original.set('name', 'yolo');
+});
+
+// Prevent LiveQuery trigger unless  'foo' is modified
+Parse.Cloud.afterLiveQueryEvent('MyObject', (request) => {
+  const object = request.object;
+  const original = request.original;
+  if (!original) {
+    return;
+  }
+  if (object.get('foo') != original.get('foo')) {
+    request.sendEvent = false;
+  }
+});
+
+// Including an object on LiveQuery event, on update only.
+Parse.Cloud.afterLiveQueryEvent('MyObject', async (request) => {
+  if (request.event != "update") {
+    request.sendEvent = false;
+    return;
+  }
+  const object = request.object;
+  const pointer = object.get("child");
+  await pointer.fetch();
+});
+
+//Extend matchesQuery functionality to LiveQuery
+Parse.Cloud.afterLiveQueryEvent('MyObject', async (request) => {
+  if (request.event != "Create") {
+    return;
+  }
+  const query = request.object.relation('children').query();
+  query.equalTo('foo','bart');
+  const first = await query.first();
+  if (!first)  {
+    request.sendEvent = false;
+  }
+});
+```
+
+### Some considerations to be aware of
+- Live Query events won't trigger until the `afterLiveQueryEvent` trigger has completed. Make sure any functions inside the trigger are efficient and restrictive to prevent bottlenecks.
+
 ## onLiveQueryEvent
 
 *Available only on parse-server cloud code starting 2.6.2*