Google Tag Manager uses the dataLayer array as a message queue.
Anything that is pushed into dataLayer is processed by Google Tag Manager in order (first in, first out).
GTM "listens" to dataLayer.push() calls by adding its own listener to the method. For this reason, it's imperative that you never overwrite this listener.
However, there might be cases where you want to add your own listener to the dataLayer.push method, too, in case you want to debug it outside Google Tag Manager or if you want to dynamically add information to all objects that pass through it. This leads us to the question we'll be discussing in this video:
"How do I add my own listener to the dataLayer.push() method without disrupting how Google Tag Manager works?"
In the video (and the linked article below), I'll first show you the JavaScript pattern you can use to override the dataLayer.push with your own function expression. The pattern we'll use "protects" Google Tag Manager's implementation, so you can rest assured that even with your side effects in place, GTM won't break.
I'll also share three use cases where overriding the dataLayer.push method like this might come in handy. The use cases are:
#1 - Log the pushed arguments into the JavaScript console.
#2 - Add a timestamp dynamically to all pushed objects.
#3 - Log the computed state of Google Tag Manager's internal data model after each push.
You can read the relevant article with all the code samples here: www.teamsimmer.com/2023/03/14...
KEY MOMENTS
00:00 Intro
00:23 The question we'll be discussing in this video
01:00 How GTM works with dataLayer
02:04 The JavaScript pattern to override dataLayer.push
04:24 Use case #1: Log the pushed arguments
06:00 Use case #2: Add a timestamp to all pushed objects
07:15 Use case #3: Log the computed state of GTM's data model
09:27 Outro
LINKS
🔗 Simmer Newsletter
www.teamsimmer.com/newsletter/
🔗 Simmer Blog
www.teamsimmer.com/blog/
🔗 JavaScript For Digital Marketers (online course)
www.teamsimmer.com/all-course...
🔗 Technical Marketing Handbook Podcast
www.teamsimmer.com/tmh-podcast/
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