Add option to use amplitude referral behaviour (#639)

* Add option to use amplitude referral

* bump version

Author: danieljackins

integrations/amplitude/lib/index.js

@@ -53,6 +53,7 @@ var Amplitude = (module.exports = integration('Amplitude')
   .option('unsetParamsReferrerOnNewSession', false)
   .option('trackProductsOnce', false)
   .option('versionName', '')
+  .option('useAmplitudeReferral', false)
   .tag('<script src="' + src + '">'));
 
 /**
@@ -81,6 +82,7 @@ Amplitude.prototype.initialize = function() {
     includeGclid: this.options.trackGclid,
     saveParamsReferrerOncePerSession: this.options
       .saveParamsReferrerOncePerSession,
+    includeReferrer: this.options.useAmplitudeReferral,
     deviceIdFromUrlParam: this.options.deviceIdFromUrlParam,
     unsetParamsReferrerOnNewSession: this.options
       .unsetParamsReferrerOnNewSession,
@@ -144,7 +146,8 @@ Amplitude.prototype.loaded = function() {
 Amplitude.prototype.page = function(page) {
   this.setDeviceIdFromAnonymousId(page);
 
-  if (this.options.trackReferrer) this.sendReferrer();
+  if (this.options.trackReferrer && !this.options.useAmplitudeReferral)
+    this.sendReferrer();
 
   var category = page.category();
   var name = page.fullName();

integrations/amplitude/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@segment/analytics.js-integration-amplitude",
   "description": "The Amplitude analytics.js integration.",
-  "version": "3.3.2",
+  "version": "3.3.3",
   "keywords": [
     "analytics.js",
     "analytics.js-integration",