Add flag and logic to delete cross domain identifiers

lib/index.js

@@ -61,6 +61,7 @@ var Segment = exports = module.exports = integration('Segment.io')
   .option('apiKey', '')
   .option('apiHost', 'api.segment.io/v1')
   .option('crossDomainIdServers', [])
+  .option('deleteCrossDomainId', false)
   .option('retryQueue', true)
   .option('addBundledMetadata', false)
   .option('unbundledIntegrations', []);
@@ -179,6 +180,9 @@ Segment.prototype.initialize = function() {
     this.cookie('segment_cross_domain_id_timestamp', null);
   }
 
+  // Delete cross domain identifiers.
+  this.deleteCrossDomainIdIfNeeded();
+
   // At this moment we intentionally do not want events to be queued while we retrieve the `crossDomainId`
   // so `.ready` will get called right away and we'll try to figure out `crossDomainId`
   // separately
@@ -495,6 +499,41 @@ Segment.prototype.retrieveCrossDomainId = function(callback) {
   }
 };
 
+/**
+ * Deletes any state persisted by cross domain analytics.
+ * * seg_xid (and metadata) from cookies
+ * * crossDomainId from traits in localStorage
+ *
+ * The deletion logic is run only if deletion is enabled for this project, and
+ * when either the seg_xid cookie or crossDomainId localStorage trait exists.
+ *
+ * @api private
+ */
+Segment.prototype.deleteCrossDomainIdIfNeeded = function() {
+  // Only continue if deletion is enabled for this project.
+  if (!this.options.deleteCrossDomainId) {
+    return;
+  }
+
+  // Delete the xid cookie if it exists. We also delete associated metadata.
+  if (this.cookie('seg_xid')) {
+    this.cookie('seg_xid', null);
+    this.cookie('seg_xid_fd', null);
+    this.cookie('seg_xid_ts', null);
+  }
+
+  // Delete the crossDomainId trait in localStorage if it exists.
+  if (this.analytics.user().traits().crossDomainId) {
+    // This intentionally uses an internal API, so that
+    // we can avoid interacting with lower level localStorage APIs, and instead
+    // leverage existing functionality inside analytics.js.
+
+    var traits = this.analytics.user().traits();
+    delete traits.crossDomainId;
+    this.analytics.user()._setTraits(traits);
+  }
+};
+
 /**
  * getCrossDomainIdFromServers
  * @param {Array} domains

test/index.test.js

@@ -1087,6 +1087,65 @@ describe('Segment.io', function() {
               assert.equal(segment.isCrossDomainAnalyticsEnabled(), true);
             });
           });
+
+          describe('deleteCrossDomainId', function() {
+            it('should not delete cross domain identifiers by default', function() {
+              segment.cookie('seg_xid', 'test_xid');
+              analytics.identify({
+                crossDomainId: 'test_xid'
+              });
+
+              segment.deleteCrossDomainIdIfNeeded();
+
+              assert.equal(segment.cookie('seg_xid'), 'test_xid');
+              assert.equal(analytics.user().traits().crossDomainId, 'test_xid');
+            });
+
+            it('should do not delete cross domain identifiers if disabled', function() {
+              segment.options.deleteCrossDomainId = false;
+
+              segment.cookie('seg_xid', 'test_xid');
+              analytics.identify({
+                crossDomainId: 'test_xid'
+              });
+
+              segment.deleteCrossDomainIdIfNeeded();
+
+              assert.equal(segment.cookie('seg_xid'), 'test_xid');
+              assert.equal(analytics.user().traits().crossDomainId, 'test_xid');
+            });
+
+            it('should delete cross domain identifiers if enabled', function() {
+              segment.options.deleteCrossDomainId = true;
+
+              segment.cookie('seg_xid', 'test_xid');
+              analytics.identify({
+                crossDomainId: 'test_xid'
+              });
+
+              segment.deleteCrossDomainIdIfNeeded();
+
+              assert.equal(segment.cookie('seg_xid'), null);
+              assert.equal(analytics.user().traits().crossDomainId, null);
+            });
+
+            it('should not delete any other traits if enabled', function() {
+              segment.options.deleteCrossDomainId = true;
+
+              analytics.identify({
+                crossDomainId: 'test_xid',
+                name: 'Prateek',
+                age: 26
+              });
+
+              segment.deleteCrossDomainIdIfNeeded();
+
+              assert.deepEqual(analytics.user().traits(), {
+                name: 'Prateek',
+                age: 26
+              });
+            });
+          });
         });
       });
     }