From 9e012708e832a64ac55ad4c16ebb830d27460b17 Mon Sep 17 00:00:00 2001
From: abruere <andy@stelace.com>
Date: Mon, 15 Apr 2019 03:10:52 +0200
Subject: [PATCH] feat: skip tracking dynamically

Useful to ignore some lazyloaded pages or avoid
app-specific duplicate events with pageviewTemplate
---
 __tests__/lib/page.spec.js | 18 ++++++++++++++++++
 docs/page-tracking.md      |  6 +++++-
 src/lib/page.js            |  5 +++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/__tests__/lib/page.spec.js b/__tests__/lib/page.spec.js
index 0d80b6a..2e4f196 100644
--- a/__tests__/lib/page.spec.js
+++ b/__tests__/lib/page.spec.js
@@ -67,3 +67,21 @@ it ('should set and track page with a VueRouter instance', () => {
   expect(window.ga).toBeCalledWith('set', 'page', '/')
   expect(window.ga).toBeCalledWith('send', 'pageview', '/')
 })
+
+it ('should skip tracking when page first argument is a falsy value', () => {
+  $vm.$ga.page(null)
+  $vm.$ga.page(false)
+  $vm.$ga.page(undefined)
+  // Google officially states that page path must begin with '/'
+  // https://developers.google.com/analytics/devguides/collection/analyticsjs/field-reference#page
+  $vm.$ga.page('')
+
+  expect(window.ga).not.toHaveBeenCalled()
+  expect(window.ga).not.toHaveBeenCalled()
+
+  // Skip behavior must be explicit
+  $vm.$ga.page()
+
+  expect(window.ga).toHaveBeenCalled()
+  expect(window.ga).toHaveBeenCalled()
+})
diff --git a/docs/page-tracking.md b/docs/page-tracking.md
index a5896d9..c1b077d 100644
--- a/docs/page-tracking.md
+++ b/docs/page-tracking.md
@@ -164,6 +164,10 @@ const router = new VueRouter({
 ```
 important: the route pageviewTemplate has always priority over the global one.
 
+`pageviewTemplate` can return a falsy value to skip tracking, which can be useful for specific needs:
+
+- `shouldRouterUpdate` documented below is more appropriate for tracking control based on routing, but is not enough when you need to disable initial tracking on some pages, since it only applies to navigation after initial page load.
+- `pageviewOnLoad: false` is global and can’t depend on current route.
 
 ## Avoid transforming route query object into querystring
 It is possible to avoid route query to be sent as querystring using the `transformQueryString` property
@@ -206,7 +210,7 @@ Vue.use(VueAnalytics, {
 })
 ```
 
-For other use cases it is also possible to use the `shouldRouterUpdate`, accessable in the plugin configuartion object, inside the `autoTracking` property.
+For other use cases it is also possible to use the `shouldRouterUpdate`, accessible in the plugin configuration object, inside the `autoTracking` property.
 The methods has the previous and current route as parameters and it needs to return a truthy or falsy value.
 
 ```js
diff --git a/src/lib/page.js b/src/lib/page.js
index f2e2cd4..e96241e 100644
--- a/src/lib/page.js
+++ b/src/lib/page.js
@@ -11,6 +11,11 @@ import {
 } from '../helpers'
 
 export default function page (...args) {
+  if (args.length && !args[0]) {
+    // allows to dynamically prevent tracking in pageviewTemplate proxy
+    return
+  }
+
   let route
 
   if (args.length && isRouter(args[0])) {