`Error: Dynamic require of node:path is not supported` causes runtime error - how to troubleshoot?
My SvelteKit project on CF Pages builds successfully and has been great. All routes still work, except for a POST route, that gives this error.
- I do not have
node:path in my code (!)
- I have nodejs_compat enabled (screenshot)
- I removed deps and simplified this route
Cloudflare does not give a stack track, frustratingly, so I don't know how to troubleshoot further.
Any tips for how to investigate further?
6 Replies
The best way to debug things like this is locally, if you can reproduce it there, via
wrangler pages devTBH, never figured out how to set up a CF local env for SvelteKit yet...one day.
I think I may have found it!
I was able to use:
Then hit the problematic route to see the stack trace.
Stack trace implies it's due to
mime-types package I am using to convert a mime type into a file extension. https://www.npmjs.com/package/mime-types But now I have a way to keep researching. Thanks @James
Do you know if wrangler pages dev can be used with hot module reloading? I can't image waiting 30s for a build to try each change, after being used to vite dev. .... Update: it has --live-reload but since it runs SvelteKit's production build output, you have to fully rebuild before it reloads.I found an example that
npx wrangler pages dev -- npx react-scripts start but can't use with vite live reload. wrangler watch the sveltekit live reload but how to proxy the vite live result output?For SvelteKit, I have two terminals 1) npx wrangler dev (and all flags I need for D1, R2, etc). 2.) bun run build. Then I have to run “bun run build” after making any file changes and saving, bc it had to rebuild the HTML files that wrangler is watching.
I don’t know about React-related aspects
I'm hitting this too @Jason with the CF Pages/SvelteKit combo. To state the obvious... it looks like it's because a dependency is found that imports a node library like
path that is not compatible with the non-Node CF engine which is in force when running via wrangler pages dev. I only see these errors on re-loading a route and not navigating from the root URL, so I've suspected this is SSR related since first seeing this.
Running code more on the client is one way to get around this. The nuclear option is setting ssr = false and run your SvelteKit app as an SPA. I want to keep SSR and I had some components I wanted to dynamically load on the client anyways (tuning bundles) and doing so made the problem go away.
It's arisen again (why I read this thread) and looking more closely at the stack trace I can see my error is related to postcss and postcss-import in particular, which I can see does import "path". So my theory is that SvelteKit (or related dev plugins) use path in SSR rendering which is what blows up the route. I saw there was an [alias] option in wrangler.toml and I've been using pathe as an alternative, however CF is complaining that it's not a valid pages configuration so I am still looking for a fix.For my case, using
@Ben Does your stack trace from
wrangler dev exposed the full error message which let me identify it was the mime-types package that uses node's path package (https://github.com/jshttp/mime-types/issues/82), and switching to the NPM mime package solves it--I just wrote my own minimal, mime validation function instead.
I'd be dubious about SSR causing it b/c 1.) I used SSR on CF Pages previously successfully, and 2.) it's a key feature to support for each SvelteKit adapter (would be a big bug).@Ben Does your stack trace from
wrangler dev show the parent file that invokes the path module?