Document "wrangler pages functions build" command

[aantipov]

Which Cloudflare product(s) does this pertain to?

Pages

Subject Matter

"wrangler pages functions build" command

Content Location

https://developers.cloudflare.com/workers/wrangler/commands/
https://developers.cloudflare.com/pages/functions/

Additional information

Wrangler command wrangler pages functions build exists but not documented

I have to use this command to be able to instrument functions' output build and generate its sourcemap for Sentry. Otherwise, without sourcemaps, it's difficult to debug issues.

I think I'm not alone in this use case. I guess there are other use-cases which require usage of that command.

Lack of documentation makes it extremely difficult to use it - not clear what options to pass and when

[GregBrimble]

Hi! Thanks for this report. wrangler pages functions build is intentionally undocumented at the moment: https://github.com/cloudflare/workers-sdk/blob/69577b93ce56afd46668cbe556002172f1d0a0f4/packages/wrangler/src/pages/index.ts#L37-L40. We use this internally, but don't officially support this in the community, though I recognize the growing need for something like it.

We'll consider how to expose this command (or again, something similar), as we work towards Pages & Workers convergence. In the meantime, I'll close out this issue. Thanks again!

[ericmatthys]

Just a note that this command needs to be used for the Vitest integration via the globalSetup function, so it's in examples and code meant to be used by end users and not just internally.

[FraBle]

@aantipov could you elaborate how you managed to achieve the sourcemap upload for Sentry with that command? 🙏

[waynesbrain]

Cloudflare places limits on worker size and I'm trying to see if I'm going to hit any limits for my Pages functions using Hono, Kysely and TypeBox.

So far when I ran pages functions build I can see that it's bundling Kysely's esm AND cjs exports for some reason when my package.json has "type": "module" and Node compatibility is not enabled. It creates a 1.5 MiB uncompressed file. Compressed it's only about 207K so I guess it's not near the limit for a mostly empty project.

[waynesbrain]

So, this command helped me reduce the pre-compressed, pre-minified _worker.bundle for my Cloudflare Pages functions from 1.5 MiB to 660 KiB today. This command should absolutely be documented. Please, let the AIs know as well 🤣

The culprit was a package called kysely-d1 which had not published a recent pull to expose ESM bindings.

When I copied the small single-file source of kysely-d1 directly into my project and removed the dependency I got a wrangler pages functions build output of 660 KiB.

It would be nice if wrangler could report CJS-only modules like this, but at least with this command I can figure it out. Whew!

(Edit: Thunar messed me up and I originally thought it was 60 KiB, whoops!)