Add support for optional trackers by using addTracker method

README.md

@@ -107,6 +107,21 @@ The name of the `piwik.js` static resource on the Piwik server. Set this option
 
 The name of the `piwik.php` script on the Piwik server. Set this option if the Piwik instance uses a different name.
 
+### optionalTrackers: []
+
+Set a comma delimited list of Matomo servers urls for addTracker.  
+
+- The list of `url`s must match the order of urls in `optionalTrackersWebsiteId`.
+- e.g. [https://asdf.bar/piwik.php, https://qwerty.bar/piwik.php]
+
+By using this together with `optionalTrackersWebsiteId` you can track your analytics data into more than just one Matomo server or into multiple websites on the same Matomo server. See [Multiple Matomo trackers](https://developer.matomo.org/guides/tracking-javascript-guide#multiple-piwik-trackers)
+
+### optionalTrackersWebsiteId: []
+
+Set a comma delimited list of Matomo `siteId` for addTracker. Used together with `optionalTrackers`. 
+
+- The list of `siteId`s must match the order of urls in `optionalTrackers`.
+- e.g. [1, 2]
 
 ## API
 

index.js

@@ -77,6 +77,8 @@ var PiwikTracker = function(opts) {
 	opts.injectScript = ((opts.injectScript !== undefined) ? opts.injectScript : true);
 	opts.clientTrackerName = ((opts.clientTrackerName !== undefined) ? opts.clientTrackerName : 'piwik.js');
 	opts.serverTrackerName = ((opts.serverTrackerName !== undefined) ? opts.serverTrackerName : 'piwik.php');
+	opts.optionalTrackers = ((opts.optionalTrackers !== undefined) ? opts.optionalTrackers : []);
+	opts.optionalTrackersWebsiteId = ((opts.optionalTrackersWebsiteId !== undefined) ? opts.optionalTrackersWebsiteId : []);
 
 	var alreadyInitialized = piwikIsAlreadyInitialized();
 
@@ -219,6 +221,12 @@ var PiwikTracker = function(opts) {
 
 			push(['setSiteId', opts.siteId]);
 			push(['setTrackerUrl', u + opts.serverTrackerName]);
+
+			if (opts.optionalTrackers.length && opts.optionalTrackersWebsiteId.length ) {
+				for (var i in opts.optionalTrackers) {
+					push(['addTracker', opts.optionalTrackers[i], opts.optionalTrackersWebsiteId[i]]);
+				}
+			}
 		}
 
 		if (opts.userId) {

test/client.tests.js

@@ -55,6 +55,57 @@ describe('piwik-react-router client tests', function () {
     ]);
   });
 
+  it ('should correctly push the addTracker to the _paq array on instantiation if optionalTrackers and optionalTrackersWebsiteId are given', () => {
+    const piwikReactRouter = testUtils.requireNoCache('../')({
+      url: 'foo.bar',
+      siteId: 1,
+      enableLinkTracking: true,
+      optionalTrackers: ['http://bar.bar/piwik.php'],
+      optionalTrackersWebsiteId: [2]
+    });
+
+    assert.sameDeepMembers(window._paq, [
+      [ 'setSiteId', 1 ],
+      [ 'setTrackerUrl', 'http://foo.bar/piwik.php' ],
+      [ 'enableLinkTracking' ],
+      [ 'addTracker', 'http://bar.bar/piwik.php', 2]
+    ]);
+  });
+
+  it ('should correctly push multiple addTrackers to the _paq array on instantiation if optionalTrackers and optionalTrackersWebsiteId are given with multiple values', () => {
+    const piwikReactRouter = testUtils.requireNoCache('../')({
+      url: 'foo.bar',
+      siteId: 1,
+      enableLinkTracking: true,
+      optionalTrackers: ['http://bar.bar/piwik.php', 'http://qwerty.bar/piwik.php'],
+      optionalTrackersWebsiteId: [1, 2]
+    });
+
+    assert.sameDeepMembers(window._paq, [
+      [ 'setSiteId', 1 ],
+      [ 'setTrackerUrl', 'http://foo.bar/piwik.php' ],
+      [ 'enableLinkTracking' ],
+      [ 'addTracker', 'http://bar.bar/piwik.php', 1],
+      [ 'addTracker', 'http://qwerty.bar/piwik.php', 2]
+    ]);
+  });
+
+  it ('should not push addTracker to the _paq array on instantiation if optionalTrackers and optionalTrackersWebsiteId are not given', () => {
+    const piwikReactRouter = testUtils.requireNoCache('../')({
+      url: 'foo.bar',
+      siteId: 1,
+      enableLinkTracking: true,
+      optionalTrackers: [],
+      optionalTrackersWebsiteId: []
+    });
+
+    assert.sameDeepMembers(window._paq, [
+      [ 'setSiteId', 1 ],
+      [ 'setTrackerUrl', 'http://foo.bar/piwik.php' ],
+      [ 'enableLinkTracking' ]
+    ]);
+  });
+
   it ('should correctly push the userId on instantiation', () => {
     const piwikReactRouter = testUtils.requireNoCache('../')({
       url: 'foo.bar',