How to Integrate Google Analytics with Astro Using Partytown

Day by Day I love Astro and its performance results, since you're reading this blog it's likely you're already using it. I will show you in this blog the best way to integrate Google Analytics (and maybe other third-party scripts like Facebook Pixel...) with the help of Partytown.

If you're unfamiliar with Partytown, It's a lazy-loaded library that helps relocate resource-intensive scripts into a web worker, and off of the main thread. Its primary goal is to help you use third-party scripts without slowing down your site.

Normally, this is the code you need to add to the head of your document


<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=YOUR-ID"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'YOUR-ID');
</script>

First, let's install Partytown:

#npm
npx astro add partytown
#pnpm
pnpm astro add partytown
#yarn
yarn astro add partytown

Create Astro component google-analytics.astro with the following content:

---
const GA_MEASUREMENT_ID = import.meta.env.GA_MEASUREMENT_ID
---

<script
  type="text/partytown"
  src=`https://www.googletagmanager.com/gtag/js?id=${GA_MEASUREMENT_ID}`
></script>
<script type="text/partytown" define:vars={{ GA_MEASUREMENT_ID }}>
  window.dataLayer = window.dataLayer || []
  window.gtag = function gtag() {
    dataLayer.push(arguments)
  }
  gtag('js', new Date())

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

I use an environment variable so if The project is open source it won't expose the measurement ID. Remember to create a .env file and include the variable as shown below:

PS: You can be added to platforms like Vercel or Netlify...

GA_MEASUREMENT_ID=YOUR-ID

Last but not least, You need to include that component in a layout or a page. There are two conditions to render the script:

Only render it in a production environment
Render it if GA_MEASUREMENT_ID is truthy (it exists). This ensures that if you didn't add it to production, you won't see an error in the console.

---
import GoogleAnalytics from '../components/google-analytics.astro'
const GA_MEASUREMENT_ID = import.meta.env.GA_MEASUREMENT_ID
const isProd = import.meta.env.PROD
---
<!doctype html>
<html lang="en">
  <head>
    <!-- Metadata tags  -->
    {isProd && GA_MEASUREMENT_ID && <GoogleAnalytics />}
  </head>
  <body>
  </body>
</html>

I have put the final code in this repository. I hope you find this article helpful. Thank you for reading.

How to Integrate Google Analytics with Astro Using Partytown: The Best Way for Optimal Performance

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