Data layer

Rename the data layer

Important: Only rename the data layer if your project requires a separate name. You will lose measurement data if you don't rename all existing references.

The default name of the data layer by the global site tag is dataLayer, to use a different name:

• Update all instances of "dataLayer" in the global site tag snippet to the new name.
• Add an query parameter named l to the URL to set the new data layer name.

<!-- Global site tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=GA_MEASUREMENT_ID&l=gDataLayer"></script>
<script>
  window.gDataLayer = window.gDataLayer || [];
  function gtag(){gDataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'GA_MEASUREMENT_ID');
</script>

Custom data layer methods

If you push a function to the data layer, it will be invoked with this set to an abstract data model. This abstract data model can get and set values to a key value store, and also exposes a way to reset the data layer.

Important: In order to use custom data layer methods, you must .push to the dataLayer variable directly. If you use the gtag global, the function will be interpreted as an invalid gtag command and ignored.

Get

The get function on the abstract data model lets you retrieve values that were set.

window.dataLayer.push(function() {
  const existingTime = this.get('time');
  if (existingTime !== null) {
    // Change behavior based on whether or not this value exists...
  } else {
    // ...
  }
})

Set

The set function on the abstract data model lets you set values to retrieve through get.

window.dataLayer.push(function() {
  this.set('time', new Date());
})

Reset

The reset function on the abstract data model lets you reset the data in the data layer. This is most useful in a long-living page where the data layer size continues to grow over time. To reset the data layer, use the following code:

window.dataLayer.push(function() {
  this.reset();
})