Google Tag Manager dataLayer persistency

Question

Summary

Google Tag Manager dataLayer gets clogged with values over time that make rules and tags too complex, especially on an AJAX-heavy site.

---

Question

I'm implementing GTM on a tracking-heavy site and looking for a clean solution to the following issue. I'll take Google Analytics as en example.

It lets you set and use 4 macros for event tracking:

• Category {{ga event category}}
• Action {{ga event action}}
• Label {{ga event label}}
• Value {{ga event value}}

Value and label are optional, but dataLayer is persistent, isn't it? So how do I handle the following scenario:

dataLayer.push({
  'event':'gaEvent', 
  'gaEventCategory':'my-category', 
  'gaEventAction':'my-action',
  'gaEventLabel':'my-label',
  'gaEventValue':'my-value'
});

But then on the same page later I have to track another event, but one without Label and Value:

dataLayer.push({
  'event':'gaEvent', 
  'gaEventCategory':'another-category', 
  'gaEventAction':'another-action',
});

If I set up a rule like "Event is gaEvent" and on that I fire off the "Google Analytics" tag that looks like the following (using HTML tag here instead of built-in one):

<script type="text/javascript">
  _gaq.push(['_trackEvent', '{{ga event category}}', '{{ga event action}}', '{{ga event label}}',  {{ga event value}}]);
</script>

The second event would be pushed to _gaq with previous event's label and value.

How to handle cases like these?

For those wondering, I need to be able to fire off different tags on the same event at certain points, that's why I want this "dynamic" solution, but dataLayer being persistent like that would screw up the Rules.

Edit 1: testing routine

Here's how I test this.

• I have Google Analytics Debugger installed in Chrome
• I have GTM in debug mode
• Once the site is loaded, in the console I do the first dataLayer push from description
• I see from GA Debug output that the GA event is fired with the 4 values
• I do the second push from the console
• GA Debug output tells me that the GA event is fired with new category and action, but with previously pushed label and value

That's the persistency I speak of. To circumvent this I could only come up with different event types like gaCustomEvent, gaCustomEventWithLabel, gaCustomEventWithOption etc, and then rules and tags for each one of those. That's absurd, don't you agree?

Answer 1

You can push an object into the dataLayer containing all of the information relevant to the individual event, e.g.:

dataLayer.push({
    'gaEvent':{
        'category': 'foo',
        'action': 'bar',
        'label': 'blah blah blah',
        'value': 1,
        'nonInteraction':false
    }
});

You can then set up the relevant macros in GTM to collect & use the relevant fields, which will not be carried over to any future events as only the last value of an object pushed into the dataLayer is used.