Path alias import fails on production

Hello! Recently I’ve started being in touch with a strange bug. It seems that the module-alias does not work on my production environment (does not matter if I run the same commands to build and start the app, it only works on development environment but not on production) 🤔

I’m currently using lerna to run all project commands because it is a project inside a monorepository. So, in practice I build the app using the following Dockerfile:

FROM node:current-stretch

RUN mkdir -p /uno

WORKDIR /uno

COPY . /uno

RUN npm run ci:unapy

ENV PORT 80

ENV NODE_ENV production

EXPOSE 80 3667

CMD [ "npm", "run", "dev:unapy" ]

So, after building this app, I try to run it with the following command:

# 'npm run dev:unapy' is the command below
node -r module-alias/register dist/index.js

Then, I receive the following logs depending on the environment I’m currently in:

• Production Environment log:

> uno-game@0.0.0 start:unapy
> lerna run start --scope @uno-game/unapy --stream

lerna notice cli v3.22.1
lerna notice filter including "@uno-game/unapy"
lerna info filter [ '@uno-game/unapy' ]
lerna info Executing command in 1 package: "npm run start"
> @uno-game/unapy@0.0.0 start
> node -r module-alias/register dist/index.js
node:internal/modules/cjs/loader:928
throw err;
^
Error: Cannot find module '@/Core'
Require stack:
- /uno/packages/unapy/dist/index.js
at Function.Module._resolveFilename (node:internal/modules/cjs/loader:925:15)
at Function.Module._resolveFilename (/uno/node_modules/module-alias/index.js:49:29)
at Function.Module._load (node:internal/modules/cjs/loader:769:27)
at Module.require (node:internal/modules/cjs/loader:997:19)
at require (node:internal/modules/cjs/helpers:92:18)
at Object.<anonymous> (/uno/packages/unapy/dist/index.js:7:32)
at Module._compile (node:internal/modules/cjs/loader:1108:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1137:10)
at Module.load (node:internal/modules/cjs/loader:973:32)
at Function.Module._load (node:internal/modules/cjs/loader:813:14) {
code: 'MODULE_NOT_FOUND',
requireStack: [ '/uno/packages/unapy/dist/index.js' ]
}
npm ERR! code 1
npm ERR! path /uno/packages/unapy
npm ERR! command failed
npm ERR! command sh -c node -r module-alias/register dist/index.js
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2021-01-19T17_05_14_611Z-debug.log
at Function.Module._resolveFilename (/uno/node_modules/module-alias/index.js:49:29)
at Function.Module._load (node:internal/modules/cjs/loader:769:27)
at Module.require (node:internal/modules/cjs/loader:997:19)
at require (node:internal/modules/cjs/helpers:92:18)
at Object.<anonymous> (/uno/packages/unapy/dist/index.js:7:32)
at Module._compile (node:internal/modules/cjs/loader:1108:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1137:10)
at Module.load (node:internal/modules/cjs/loader:973:32)
at Function.Module._load (node:internal/modules/cjs/loader:813:14) {
code: 'MODULE_NOT_FOUND',
requireStack: [ '/uno/packages/unapy/dist/index.js' ]
}
npm ERR! code 1
npm ERR! path /uno/packages/unapy
npm ERR! command failed
npm ERR! command sh -c node -r module-alias/register dist/index.js
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2021-01-19T17_05_29_914Z-debug.log
lerna ERR! npm run start exited 1 in '@uno-game/unapy'

• Development Environment log:

> uno-game@0.0.0 start:unapy /ssd/Github/uno-game
> lerna run start --scope @uno-game/unapy --stream

lerna notice cli v3.22.1
lerna notice filter including "@uno-game/unapy"
lerna info filter [ '@uno-game/unapy' ]
lerna info Executing command in 1 package: "npm run start"
@uno-game/unapy: > @uno-game/unapy@0.0.0 start /ssd/Github/uno-game/packages/unapy
@uno-game/unapy: > node -r module-alias/register dist/index.js
@uno-game/unapy: Server is running... [PORT 5000]

---

You can see some project configs below:

• Lerna package.json:

{
  "name": "uno-game",
  "version": "0.0.0",
  "private": true,
  "author": "Guilherme Mota <[e-mail]>",
  "license": "MIT",
  "scripts": {
    "setup": "npm run setup:app && npm run setup:env",
    "setup:app": "npm install && npm run install:unapy && npm run install:unoenty && npm run bootstrap",
    "setup:env": "npm run env:unapy && npm run env:unoenty",
    "bootstrap": "lerna bootstrap --use-workspaces --hoist && lerna link",
    "list": "lerna ls",
    "deploy": "lerna version",
    "install:unapy": "lerna exec --stream --scope @uno-game/unapy -- npm install",
    "build:unapy": "lerna run build --scope @uno-game/unapy --stream",
    "start:unapy": "lerna run start --scope @uno-game/unapy --stream",
    "dev:unapy": "lerna run dev --scope @uno-game/unapy --stream",
    "env:unapy": "cp packages/unapy/.env.example packages/unapy/.env",
    "install:unoenty": "lerna exec --stream --scope @uno-game/unoenty -- npm install",
    "build:unoenty": "lerna run build --scope @uno-game/unoenty --stream",
    "env:unoenty": "cp packages/unoenty/.env.example packages/unoenty/.env",
    "ci:unapy": "npm install && npm run install:unapy && npm run bootstrap && npm run build:unapy",
    "ci:unoenty": "npm install && npm run install:unoenty && npm run bootstrap && npm run build:unoenty"
  },
  "devDependencies": {
    "@typescript-eslint/eslint-plugin": "^3.7.0",
    "@typescript-eslint/parser": "^3.7.0",
    "cross-env": "^7.0.2",
    "eslint": "^6.6.0",
    "eslint-config-standard": "^14.1.1",
    "eslint-import-resolver-typescript": "^2.0.0",
    "eslint-plugin-flowtype": "^5.2.0",
    "eslint-plugin-import": "^2.22.0",
    "eslint-plugin-jsx-a11y": "^6.3.1",
    "eslint-plugin-node": "^11.1.0",
    "eslint-plugin-promise": "^4.2.1",
    "eslint-plugin-react": "^7.20.3",
    "eslint-plugin-react-hooks": "^4.0.8",
    "eslint-plugin-standard": "^4.0.1",
    "git-commit-msg-linter": "^2.4.3",
    "husky": "^4.2.5",
    "lerna": "^3.20.2",
    "lint-staged": "^10.2.10",
    "typescript": "^3.9.2"
  },
  "workspaces": [
    "packages/*",
    "packages/shared/*"
  ]
}

• App package.json:

{
  "name": "@uno-game/unapy",
  "version": "0.0.0",
  "description": "The UNO Game API",
  "main": "dist/index.js",
  "scripts": {
    "start": "node -r module-alias/register dist/index.js",
    "dev": "nodemon src/index.ts",
    "dev:resources": "docker-compose up",
    "build": "rm -rf dist && tsc && cp -r src/Assets dist/Assets",
    "typecheck": "tsc --noEmit"
  },
  "devDependencies": {
    "@types/cors": "^2.8.6",
    "@types/express": "^4.17.6",
    "@types/node": "^14.0.1",
    "@types/socket.io": "^2.1.8",
    "@types/uuid": "^8.0.0",
    "nodemon": "^2.0.4",
    "sucrase": "^3.15.0",
    "tsconfig-paths": "^3.9.0",
    "@uno-game/protocols": "*"
  },
  "dependencies": {
    "cors": "^2.8.5",
    "dotenv": "^8.2.0",
    "express": "^4.17.1",
    "module-alias": "^2.2.2",
    "socket.io": "^2.3.0",
    "socket.io-msgpack-parser": "^2.2.0",
    "@uno-game/error-handler": "*"
  },
  "optionalDependencies": {
    "@uno-game/protocols": "*",
    "@uno-game/error-handler": "*"
  },
  "_moduleAliases": {
    "@": "dist"
  }
}

[randal923]

I fixed it. I had this in my package.json:

"_moduleAliases": {
    "@": "src"
  }

I changed it to this:

"_moduleAliases": {
    "@": "dist"
  }

[guilhermebkel]

Hello guys! Thanks for giving a feedback about my error!

At first, @randal923 I had already used these configurations and it didn’t work 😔, I would like to give you a huge thanks for offering a help on discord to me, but before I tried to get in touch with you, I’ve tried the tip that @danielrhodes has given in the last comment and it worked like a charm! It really looks like an issue of this module behavior when dealing with workspaces (so adding the module alias config in the root package.json really works).

A huge thanks for all the help!