> ## Documentation Index
> Fetch the complete documentation index at: https://resq-dependabot-github-actions-github-actions-478e18be3d.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# SanitizeGa4Id

# Function: sanitizeGa4Id()

> **sanitizeGa4Id**(`id`): `string` | `null`

Defined in: [resq.ts:69](https://github.com/resq-software/npm/blob/fe2e20ae9db8398a0db1e3218edaabb3cf7004d6/packages/analytics/src/resq.ts#L69)

Validate a GA4 Measurement ID against [GA4\_ID\_PATTERN](../variables/GA4_ID_PATTERN).

## Parameters

### id

`string` | `null` | `undefined`

The candidate ID, typically `import.meta.env.VITE_GA4_ID`
or `process.env.NEXT_PUBLIC_GA4_ID`. Accepts `null`/`undefined` for
convenience so call sites don't need a guard around env-var reads
or nullable config fields.

## Returns

`string` | `null`

The validated ID when it matches Google's format, otherwise
`null`. Skip GA4 init entirely when this returns `null`.