@astrojs/vercel: Fix vercel analytics id not being provided

[nblackburn]

While testing out vercel analytics using the vercel adapter, I noticed there was an error in my console stating that VERCEL_ANALYTICS_ID has not been provided.

After some research it looks as though it is looking for PUBLIC_VERCEL_ANALYTICS_ID but it is never provided. I believe this is likely the cause of the error.

packages/integrations/vercel/src/analytics.ts

Running vc pull with the analytics enabled downloads an environment locally which contains VERCEL_ANALYTICS_ID and not PUBLIC_VERCEL_ANALYTICS_ID. The documentation also mentions that the environment variable is inlined at build time.

https://vercel.com/docs/concepts/analytics/api#getting-started

To use the Web Vitals API, you'll need to retrieve the analytics ID for your Vercel project. This value is exposed during the build and can be accessed by process.env.VERCEL_ANALYTICS_ID inside Node.js.

Changes

• Fix wrong environment variable being used
• Added changeset

Testing

• Added the missing environment variable to my build and redeployed, and it worked.
• Ran test suite and one test fails, which I believe falls outside the scope of this change.
• I have kept the builds up which demonstrate the workaround I put together before making any changes.

Before fix: https://welcome-to-astro-7lrfynd8t-nblackburn.vercel.app/
After fix: https://welcome-to-astro-irzdnom89-nblackburn.vercel.app/

Docs

With this being, an internal change, I don't believe it requires any changes to the documentation.

/cc @withastro/maintainers-docs for feedback!

[changeset-bot]

🦋 Changeset detected

Latest commit: 4987702

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[bluwy]

This make sense to me, and thanks for extensively testing it too. Don't think it would be a breaking change either as VERCEL_ANALYTICS_ID would be set by default as you mentioned.

[nblackburn]

@bluwy Exactly, thanks for the review 👍

[tonyski]

@nblackburn Hi, I updated this change, and i can log process.env.VERCEL_ANALYTICS_ID value.
but the site still shows: [Analytics] VERCEL_ANALYTICS_ID not found.
what is the problem?
Example link: https://astro-3btbig79z-naddod-kaka.vercel.app

[nblackburn]

@tonyski In my efforts to find out why the key wasn't being included, allowed myself to lose track of the fact that only environment variables that are prefixed with PUBLIC_ will be bundled at build time. I will put a change in to revert it shortly 👍

At least for me, that environment variable isn't being provided unless I specifically set it myself.