# Using Google Optimize in a plugin initializer JS

**URL:** <https://meta.discourse.org/t/using-google-optimize-in-a-plugin-initializer-js/184865>\
**Category:** Product Support\
**Created:** [March 30, 2021, 4:17pm UTC](https://meta.discourse.org/t/using-google-optimize-in-a-plugin-initializer-js/184865 "2021-03-30T16:17:33Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![Ali\_Hassan](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/ali_hassan/32/215114_2.png) [@Ali\_Hassan](https://meta.discourse.org/u/Ali_Hassan)\
**Post date:** [March 30, 2021, 4:17pm UTC](https://meta.discourse.org/t/using-google-optimize-in-a-plugin-initializer-js/184865/1 "2021-03-30T16:17:34Z")

</div>

Hey everyone, i have a problem when i enable v4\_gtag for analytics instead of v3\_analytics, i need GTag for Google Optimize but i keep getting an error that `gtag is not a function`.

i am calling the `gtag` function inside a plugin js file, can someone provide more context on why this isn’t working ?

here is a sample of how i’ve written the code, Thank you in advance

```plaintext
export default {
  name: 'common-init',
  after: 'inject-objects',
  initialize() {
    gtag('event', 'optimize.callback', {
      name: settings.optimize_js_experiment_id,
      callback: (variation) => {
       console.log(`Variation: ${variation}`)
      }
    })
  }
}

```

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