Vercel build cannot resolve src/* path aliases in NestJS project

(edited)

Hi Vercel team

I’m deploying a NestJS project to Vercel and hitting an issue with module resolution. On local development and other hosting providers, my imports like this work fine:

import Roles from 'src/common/guards/verify-jwt.guard'

When deployed to Vercel, the build succeeds but runtime fails with: error

this is i define databaseModule :

import { DatabaseModule } from 'src/modules/database/database.module';

i think the error because vercel cannot understand the "src" path, i founded the solution by remove the src/ and write actual manual path like "../../..." instead of "src/" but it have more than 50 constants and props imported automaticly, so what is your suggestion to fix that?

Seeing this same issue, with a slightly different error logged:

Cannot find module '@api/auth/auth.module'
Require stack:
- /var/task/apps/api/src/app.module.js
- /var/task/apps/api/src/main.js
Did you forget to add it to "dependencies" in `package.json`?
Node.js process exited with exit status: 1. The logs above can help with debugging the issue.

Looks to me like it is finding the proper .js files but somewhere in the import chain it starts looking at the uncompiled aliased paths instead of the built relative ones.

I also don’t see it as a feasible solution to skip using import aliases in a large codebase, especially a monorepo.

Vercel Staff

Hi , I'm sorry you are facing this issue. Can you share a public repo or a minimal reproducible example. That will let us all work together from the same code to figure out what’s going wrong.

What does your tsconfig look like?

Absolutely, here’s an attempt at a minimal repro:

https://github.com/fullystudios/nestjs-monorepo-vercel-repro

GitHub

GitHub - fullystudios/nestjs-monorepo-vercel-repro

Contribute to fullystudios/nestjs-monorepo-vercel-repro development by creating an account on GitHub.

Here’s the Vercel project, if you can check the logs:

https://vercel.com/fully-studios-team/nestjs-monorepo-vercel-repro-api/logs

Vercel Staff

Hi , thanks. Let me try to recreate this.

Also seeing this present in the same way

Vercel Staff

Hi , welcome to the Vercel Community!

I found the following solution from a StackOverflow post:

The solution (for now, at least) is to replace all your imports with relative paths, like so :

from -> import { UsersService } from 'src/users/users.service';

to ----> import { UsersService } from '../users/users.service';

Have you tried this?

Would you really expect someone to rewrite all the imports from the src alias (it is a standard in Nest.js) to infinite “../../../../”?

Vercel Staff

Hi , just checking in on your issue with the Vercel build and path aliases in your NestJS project. Did you manage to find a solution, or do you still need assistance? Happy to help.

Hello , I am not sure about the creator of this issue, but I’m having the same problem with NestJS and the src alias right not. I guess it’s a structural issue on the Vercel side, and not using the “src” aliases is not a good solution. Are there plans for a fix?

Thank you in advance

This topic is closed. It no longer accepts new replies.

Hi Vercel team

I’m deploying a NestJS project to Vercel and hitting an issue with module resolution. On local development and other hosting providers, my imports like this work fine:

import Roles from 'src/common/guards/verify-jwt.guard'

When deployed to Vercel, the build succeeds but runtime fails with: error

this is i define databaseModule :

import { DatabaseModule } from 'src/modules/database/database.module';

Cannot find module '@api/auth/auth.module' Require stack: - /var/task/apps/api/src/app.module.js - /var/task/apps/api/src/main.js Did you forget to add it to "dependencies" in `package.json`? Node.js process exited with exit status: 1. The logs above can help with debugging the issue.