Add trackInteraction predicate function option

- Allows vue-matomo to ignore some types of router interactions with a
  predicate function

README.md

@@ -109,6 +109,15 @@ Vue.use(VueMatomo, {
   // ]
   preInitActions: [],
 
+  // A function to determine whether to track a router page change.  If not a function
+  // all interactions will be tracked.  Receives both the new route and the previous route
+  // and returns either true or false.  True if the interaction should be tracked, false
+  // if the interaction should be ignored
+  // Default: undefined
+  // Example: (to, from) => {
+  //   return !(from && to.path === from.path)
+  // }
+  trackInteraction: undefined,
   // A function to determine whether to track an interaction as a site search
   // instead of as a page view. If not a function, all interactions will be
   // tracked as page views. Receives the new route as an argument, and

src/index.js

@@ -10,6 +10,7 @@ const defaultOptions = {
   requireConsent: false,
   trackInitialView: true,
   trackSiteSearch: false,
+  trackInteraction: undefined,
   trackerFileName: 'matomo',
   trackerUrl: undefined,
   trackerScriptUrl: undefined,
@@ -23,6 +24,10 @@ const defaultOptions = {
 export const matomoKey = 'Matomo'
 
 function trackUserInteraction (options, to, from) {
+  if (typeof options.trackInteraction === 'function' && !options.trackInteraction(to, from)) {
+    return
+  }
+
   if (typeof options.trackSiteSearch === 'function') {
     const siteSearch = options.trackSiteSearch(to)
     if (siteSearch) {