posthog-node@4.5 breaks build on SvelteKit for Cloudflare

[ccremer]

Bug description

> Using @sveltejs/adapter-cloudflare
✘ [ERROR] Could not resolve "node:fs"

    node_modules/posthog-node/lib/index.esm.js:2:33:
      2 │ import { createReadStream } from 'node:fs';
        ╵                                  ~~~~~~~~~

  Cannot use "node:fs" when deploying to Cloudflare.


✘ [ERROR] Could not resolve "node:readline"

    node_modules/posthog-node/lib/index.esm.js:3:32:
      3 │ import { createInterface } from 'node:readline';
        ╵                                 ~~~~~~~~~~~~~~~

  Cannot use "node:readline" when deploying to Cloudflare.

How to reproduce

1. Have a SvelteKit project
2. Use adapter-cloudflare and posthog-node
3. Import posthog-node somewhere in code
4. npm run build

Related sub-libraries

• All of them
• posthog-web
• posthog-node
• posthog-react-native

Additional context

Version 4.4.1 worked just fine.

[marandaneto]

@PostHog/team-error-tracking

[oliverb123]

Thanks for the report! It looks like cloudflare workers aren't a nodejs compatible runtime by default, and you'll need to turn on the nodejs_compat flag in order to use npm packages designed for use with the nodejs runtime. Based on cloudflares compatibility matrix, with this flag enabled, the imports listed should be supported.

[ccremer]

I have this nodejs_compat flag already enabled, both in wrangler.toml, and in the dashboard.

compatibility_date = "2024-11-11"
compatibility_flags = [ "nodejs_compat" ]

However, I've found out that with adapter-cloudflare@4.9.0 it doesn't build, but it does @5.0.3.
I'm guessing since 5.0.0 node support is much better, but it might be relevant to mention the minimum versions in your docs as well.

Anyway, it works for me now. Thanks!

[ccremer]

Hm, maybe I closed it prematurely...
It builds, locally and in CF, but I still can't get a deployment up:

19:50:33.507 | ✓ built in 14.93s
19:50:33.507 |  
19:50:33.508 | Run npm run preview to preview your production build locally.
19:50:33.508 |  
19:50:33.508 | > Using @sveltejs/adapter-cloudflare
19:50:33.515 | ✔ done
19:50:33.665 | Finished
19:50:34.585 | Checking for configuration in a Wrangler configuration file (BETA)
19:50:34.586 |  
19:50:34.587 | Found wrangler.toml file. Reading build configuration...
19:50:35.683 | A wrangler.toml file was found but it does not appear to be valid. Did you mean to use wrangler.toml to configure Pages? If so, then make sure the file is valid and contains the `pages_build_output_dir` property. Skipping file and continuing.
19:50:35.683 | Found _worker.js in output directory. Uploading.
19:50:35.690 | ⛅️ wrangler 3.101.0
19:50:35.691 | -------------------
19:50:36.933 | ✨ Compiled Worker successfully
19:50:38.050 | Found _routes.json in output directory. Uploading.
19:50:38.062 | Validating asset output directory
19:50:40.685 | Deploying your site to Cloudflare's global network...
19:50:42.404 | Parsed 2 valid header rules.
19:50:43.877 | Uploading... (45/64)
19:50:44.299 | Uploading... (51/64)
19:50:44.528 | Uploading... (57/64)
19:50:44.581 | Uploading... (64/64)
19:50:44.582 | ✨ Success! Uploaded 19 files (45 already uploaded) (1.29 sec)
19:50:44.582 |  
19:50:44.973 | ✨ Upload complete!
19:50:46.908 | Uploading to dependency cache
19:50:46.962 | Skipping build output cache as it's not supported for your project
19:50:48.156 | Success: Dependencies uploaded to build cache.
19:50:49.073 | Success: Assets published!
19:50:50.980 | Error: Failed to publish your Function. Got error: Uncaught Error: No such module "node:fs".   imported from "functionsWorker-0.9051079702222944.js"

But I'm not sure what the problem is, could be a bug on CF as well.