SvelteKit production build does not work like a local one with Node driver - how to trace which package is to blame?

Question

I have a SvelteKit application that does not work after build. It is supposed to be run as a container. In one of the server endpoints I use bullmq client, which, after referenced, produces an error:

gui  | ReferenceError: module is not defined in ES module scope
gui  | This file is being treated as an ES module because it has a '.js' file extension and '/app/package.json' contains "type": "module". To treat it as a CommonJS script, rename it to use the '.cjs' file extension.
gui  |     at getPkgJsonDir (file:///app/build/server/chunks/_server-DJYoxZ8R.js:47284:40)
gui  |     at new ScriptLoader (file:///app/build/server/chunks/_server-DJYoxZ8R.js:46970:25)
gui  |     at file:///app/build/server/chunks/_server-DJYoxZ8R.js:47336:1
gui  |     at ModuleJob.run (node:internal/modules/esm/module_job:218:25)
gui  |     at async ModuleLoader.import (node:internal/modules/esm/loader:329:24)
gui  |     at async respond (file:///app/build/server/index.js:3524:22)
gui  |     at async Array.ssr (file:///app/build/handler.js:1243:3)

I guess a package tries to load a CJS package and fails, but how can I find which package is responsible for the error?

Answer 1

Moving the bullmq package from dev dependencies into dependencies solved the problem.