Can't resolve 'fs' but in an API route???

Any idea why this error is occuring? I thought all api routes are node compatible...

Module not found: Can't resolve 'fs'

https://nextjs.org/docs/messages/module-not-found

Import trace for requested module:
./node_modules/langchain/dist/document_loaders/fs/pdf.js
./node_modules/langchain/document_loaders/fs/pdf.js
./src/app/api/chat/route.ts
./node_modules/next/dist/build/webpack/loaders/next-edge-app-route-loader/index.js?absolutePagePath=%2Fhome%2Fphilip%2Fpersonal%2Faiwirk%2Fsrc%2Fapp%2Fapi%2Fchat%2Froute.ts&page=%2Fapi%2Fchat%2Froute&appDirLoader=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&nextConfigOutput=&preferredRegion=&middlewareConfig=e30%3D!

Module not found: Can't resolve 'fs'

https://nextjs.org/docs/messages/module-not-found

Import trace for requested module:
./node_modules/langchain/dist/document_loaders/fs/pdf.js
./node_modules/langchain/document_loaders/fs/pdf.js
./src/app/api/chat/route.ts
./node_modules/next/dist/build/webpack/loaders/next-edge-app-route-loader/index.js?absolutePagePath=%2Fhome%2Fphilip%2Fpersonal%2Faiwirk%2Fsrc%2Fapp%2Fapi%2Fchat%2Froute.ts&page=%2Fapi%2Fchat%2Froute&appDirLoader=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&nextConfigOutput=&preferredRegion=&middlewareConfig=e30%3D!

  "dependencies": {
    "@types/node": "20.3.2",
    "@types/react": "18.2.14",
    "@types/react-dom": "18.2.6",
    "autoprefixer": "10.4.14",
    "eslint": "8.43.0",
    "eslint-config-next": "13.4.7",
    "langchain": "^0.0.99",
    "next": "13.4.7",
    "pdf-parse": "^1.1.1",
    "postcss": "8.4.24",
    "react": "18.2.0",
    "react-dom": "18.2.0",
    "tailwindcss": "3.3.2",
    "typescript": "5.1.6",
    "zlib": "^1.0.5"
  }

  "dependencies": {
    "@types/node": "20.3.2",
    "@types/react": "18.2.14",
    "@types/react-dom": "18.2.6",
    "autoprefixer": "10.4.14",
    "eslint": "8.43.0",
    "eslint-config-next": "13.4.7",
    "langchain": "^0.0.99",
    "next": "13.4.7",
    "pdf-parse": "^1.1.1",
    "postcss": "8.4.24",
    "react": "18.2.0",
    "react-dom": "18.2.0",
    "tailwindcss": "3.3.2",
    "typescript": "5.1.6",
    "zlib": "^1.0.5"
  }

Thanks a lot

7 Replies

mferino•12mo ago

Hey Philip, does this SO post help? https://stackoverflow.com/questions/64926174/module-not-found-cant-resolve-fs-in-next-js-application

Stack Overflow

Module not found: Can't resolve 'fs' in Next.js application

Unable to identify what's happening in my next.js app. As fs is a default file system module of nodejs. It is giving the error of module not found.

philip.2000•12mo ago

I mean, I only use fs in the API route. Do I really need to change the next config? Feels a bit weird since app router is pretty server-first, isn't it? I think I found the problem

mferino•12mo ago

Ahh nice what is it?

philip.2000•12mo ago

Seems like the nextRuntime cannot be edge but has to be nodejs.

mferino•12mo ago

oic, good find!

philip.2000•12mo ago

Thanks for the help

mferino•12mo ago

yw! glad you found an answer 🙂

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Can't resolve 'fs' but in an API route???