Sends any GA hits to GTM for extra processing. Put this file directly after the ga create call.

Forward GA Hit to GTM via datalayer

/*
 This code should be put directly after the ga create call, before any hits are fired to ensure 
 it captures all hits being sent to ga.
 
 When any ga hit is fired, this code will capture it, fire the proper hit into GA and then forward
 the hit query parameters to GTM via a dataLayer event.
 
 The dataLayer event is called "gaHitTask" and the query parameters are sent in the "gaHitTaskParams" variable.

 You can use code something similar to this: https://gist.github.com/MatthewDaniels/388fa1e0c02613f103f00a504ed58c55 
 to parse the gaHitTaskParams in GTM into a map to then use elsewhere in GTM - send to your GA for instance.
*/
ga(function(tracker) {
     // Grab a reference to the default sendHitTask function.
      var originalSendHitTask = tracker.get('sendHitTask');

      // Modifies sendHitTask to send a copy of the request to GTM via a dataLayer event after
      // sending the normal request to www.google-analytics.com/collect.
      tracker.set('sendHitTask', function(model) {
        
        // sends the original hit task to GA
        originalSendHitTask(model);

        // grab a copy of the hitPayload
        var query = model.get('hitPayload');
        
        // create the dataLayer variable if it does not exist
        window.dataLayer = window.dataLayer || [];
        
        // push an event with the name gaHitTask and the gaHitTaskParams as the query payload to the dataLayer for parsing in GTM
        window.dataLayer.push({
          'event': 'gaHitTask',
          'gaHitTaskParams': query
        });
        
        ///////////////////////////////////////////////
        // REMOVE THESE CONSOLE LOGS FOR PRODUCTION
        ///////////////////////////////////////////////
        // console.log('1:', query);
        // console.log('2:', model);
    });
});