HGI 81 - Add event ID to page calls sent to FB Pixel for deduplication (#701)

* Added messageId as eventId in Facebook Pixel

* Bump facebook-pixel version

* added a unit test case for page view event

Co-authored-by: Gaurav Kochar <[email protected]>

Author: sayan-das-in

integrations/facebook-pixel/lib/index.js

@@ -135,8 +135,8 @@ FacebookPixel.prototype.loaded = function() {
  * @param {Facade} identify
  */
 
-FacebookPixel.prototype.page = function() {
-  window.fbq('track', 'PageView');
+FacebookPixel.prototype.page = function(track) {
+  window.fbq('track', 'PageView', {}, { eventID: track.proxy('messageId') });
 };
 
 /**

integrations/facebook-pixel/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@segment/analytics.js-integration-facebook-pixel",
   "description": "The Facebook Pixel analytics.js integration.",
-  "version": "2.11.4",
+  "version": "2.11.5",
   "keywords": [
     "analytics.js",
     "analytics.js-integration",

integrations/facebook-pixel/test/index.test.js

@@ -14,6 +14,16 @@ function assertEventId(spy) {
     throw new Error('Expected eventId on window.fbq.call. Not found.');
   }
 }
+/**
+ * Event ID is generated automatically by Analytics.js, this function
+ * only checks that it was succesfully added as an 4th argument in PageView to a `window.fbq` call.
+ */
+
+function assertEventIdInPageView(spy) {
+  if (!spy.args[0][3].eventID.startsWith('ajs-')) {
+    throw new Error('Expected eventId on window.fbq.call. Not found.');
+  }
+}
 
 describe('Facebook Pixel', function() {
   var analytics;
@@ -256,9 +266,10 @@ describe('Facebook Pixel', function() {
         analytics.stub(window, 'fbq');
       });
 
-      it('should track a pageview', function() {
+      it('should track a pageview along with eventID', function() {
         analytics.page();
-        analytics.called(window.fbq, 'track', 'PageView');
+        analytics.called(window.fbq, 'track', 'PageView', {});
+        assertEventIdInPageView(window.fbq);
       });
     });