reload cookie when logging event

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * Add support for passing callback function to identify.
 * Add support for prepend user property operation.
+* Keeping sessions and event metadata in sync across multiple windows/tabs.
 
 ### 2.9.1 (March 6, 2016)
 

amplitude.js

@@ -669,6 +669,7 @@ Amplitude.prototype._logEvent = function(eventType, eventProperties, apiProperti
     callback = null;
   }
 
+  _loadCookieData(this);
   if (!eventType || this.options.optOut) {
     if (callback) {
       callback(0, 'No request sent');

src/amplitude.js

@@ -563,6 +563,7 @@ Amplitude.prototype._logEvent = function(eventType, eventProperties, apiProperti
     callback = null;
   }
 
+  _loadCookieData(this);
   if (!eventType || this.options.optOut) {
     if (callback) {
       callback(0, 'No request sent');

test/amplitude.js

@@ -1621,6 +1621,31 @@ describe('Amplitude', function() {
         'nested_object': {'k':'v', 'l':[0,1], 'o':{'k2':'v2', 'l2': ['e2']}}
       });
     });
+
+    it('should synchronize event data across multiple amplitude instances that share the same cookie', function() {
+      // this test fails if logEvent does not reload cookie data every time
+      var amplitude1 = new Amplitude();
+      amplitude1.init(apiKey, null, {batchEvents: true, eventUploadThreshold: 5});
+      var amplitude2 = new Amplitude();
+      amplitude2.init(apiKey, null, {batchEvents: true, eventUploadThreshold: 5});
+
+      amplitude1.logEvent('test1');
+      amplitude2.logEvent('test2');
+      amplitude1.logEvent('test3');
+      amplitude2.logEvent('test4');
+      amplitude2.identify(new amplitude2.Identify().set('key', 'value'));
+      amplitude1.logEvent('test5');
+
+      // the event ids should all be sequential since amplitude1 and amplitude2 have synchronized cookies
+      var eventId = amplitude1._unsentEvents[0]['event_id'];
+      assert.equal(amplitude2._unsentEvents[0]['event_id'], eventId + 1);
+      assert.equal(amplitude1._unsentEvents[1]['event_id'], eventId + 2);
+      assert.equal(amplitude2._unsentEvents[1]['event_id'], eventId + 3);
+
+      var sequenceNumber = amplitude1._unsentEvents[0]['sequence_number'];
+      assert.equal(amplitude2._unsentIdentifys[0]['sequence_number'], sequenceNumber + 4);
+      assert.equal(amplitude1._unsentEvents[2]['sequence_number'], sequenceNumber +  5);
+    });
   });
 
   describe('optOut', function() {