send anonymousId automatically

Author: Han Kim

lib/index.js

@@ -83,8 +83,10 @@ GTM.prototype.page = function(page) {
 
 GTM.prototype.track = function(track) {
   var props = track.properties();
-  var id = this.analytics.user().id();
-  if (id) props.userId = id;
+  var userId = this.analytics.user().id();
+  var anonymousId = this.analytics.user().anonymousId();
+  if (userId) props.userId = userId;
+  if (anonymousId) props.anonymousId = anonymousId;
   props.event = track.event();
 
   push(props);

test/index.test.js

@@ -63,19 +63,28 @@ describe('Google Tag Manager', function() {
       });
 
       it('should send event', function() {
+        var anonId = analytics.user().anonymousId();
         analytics.track('some-event');
-        analytics.called(window.dataLayer.push, { event: 'some-event' });
+        analytics.called(window.dataLayer.push, { anonymousId: anonId, event: 'some-event' });
       });
 
       it('should send userId if it exists', function() {
         analytics.user().id('pablo');
+        var anonId = analytics.user().anonymousId();
         analytics.track('some-event');
-        analytics.called(window.dataLayer.push, { userId: 'pablo', event: 'some-event' });
+        analytics.called(window.dataLayer.push, { anonymousId: anonId, userId: 'pablo', event: 'some-event' });
+      });
+
+      it('should send anonymousId if it exists', function() {
+        analytics.user().anonymousId('el');
+        analytics.track('stranger things');
+        analytics.called(window.dataLayer.push, { anonymousId: 'el', event: 'stranger things' });
       });
 
       it('should send event with properties', function() {
+        var anonId = analytics.user().anonymousId();
         analytics.track('event', { prop: true });
-        analytics.called(window.dataLayer.push, { event: 'event', prop: true });
+        analytics.called(window.dataLayer.push, { anonymousId: anonId, event: 'event', prop: true });
       });
     });
 
@@ -91,9 +100,11 @@ describe('Google Tag Manager', function() {
 
       it('should track unamed pages if enabled', function() {
         gtm.options.trackAllPages = true;
+        var anonId = analytics.user().anonymousId();
         analytics.page();
         analytics.called(window.dataLayer.push, {
           event: 'Loaded a Page',
+          anonymousId: anonId,
           path: window.location.pathname,
           referrer: document.referrer,
           title: document.title,
@@ -103,9 +114,11 @@ describe('Google Tag Manager', function() {
       });
 
       it('should track named pages by default', function() {
+        var anonId = analytics.user().anonymousId();
         analytics.page('Name');
         analytics.called(window.dataLayer.push, {
           event: 'Viewed Name Page',
+          anonymousId: anonId,
           name: 'Name',
           path: window.location.pathname,
           referrer: document.referrer,
@@ -116,9 +129,11 @@ describe('Google Tag Manager', function() {
       });
 
       it('should track named pages with a category added', function() {
+        var anonId = analytics.user().anonymousId();
         analytics.page('Category', 'Name');
         analytics.called(window.dataLayer.push, {
           event: 'Viewed Category Name Page',
+          anonymousId: anonId,
           category: 'Category',
           name: 'Name',
           path: window.location.pathname,
@@ -130,10 +145,12 @@ describe('Google Tag Manager', function() {
       });
 
       it('should track categorized pages by default', function() {
+        var anonId = analytics.user().anonymousId();
         analytics.page('Category', 'Name');
         analytics.called(window.dataLayer.push, {
           event: 'Viewed Category Name Page',
           category: 'Category',
+          anonymousId: anonId,
           name: 'Name',
           path: window.location.pathname,
           referrer: document.referrer,