Using Cloudflare-only runtime leads to an error during the build step

[VladimirKras]

What version of Remix are you using?

2

Are all your remix dependencies & dev-dependencies using the same version?

• [X] Yes

Steps to Reproduce

run npx create-remix --template remix-run/remix/templates/cloudflare-pages

Add app/routes/example.tsx that contains

 import { EmailMessage } from "cloudflare:email";
 export const action = () => {
   console.log(EmailMessage);
   return null;
 };

run npm run build

Expected Behavior

Build succeeds on Cloudflare: info built

Actual Behavior

Build fails:

✘ [ERROR] Could not resolve "cloudflare:email"

    app/routes/example.ts:1:29:
      1 │ import { EmailMessage } from "cloudflare:email";
        ╵                              ~~~~~~~~~~~~~~~~~~

  You can mark the path "cloudflare:email" as external to exclude it from the bundle, which will remove this error.

[MurmeltierS]

experiencing this with cloudlfare:sockets

[sergiodxa]

Since the build runs on Node it can't access those packages, try to move them to the Cloudflare server file and use getLoadContext to inject them into your Remix app.