Heroku Error: Cannot find module './common'

Question

I was trying to deploy a practice project to Heroku and it gets deployed. However there is a application error, which is preventing the app to run on the server. I got some details about the errors, after running heroku logs.

2022-03-07T01:25:09.883329+00:00 app[web.1]: node:internal/modules/cjs/loader:936
2022-03-07T01:25:09.883379+00:00 app[web.1]: throw err;
2022-03-07T01:25:09.883379+00:00 app[web.1]: ^
2022-03-07T01:25:09.883379+00:00 app[web.1]:
2022-03-07T01:25:09.883380+00:00 app[web.1]: Error: Cannot find module './common'
2022-03-07T01:25:09.883380+00:00 app[web.1]: Require stack:
2022-03-07T01:25:09.883380+00:00 app[web.1]: - /app/node_modules/debug/src/node.js
2022-03-07T01:25:09.883381+00:00 app[web.1]: - /app/node_modules/debug/src/index.js
2022-03-07T01:25:09.883381+00:00 app[web.1]: - /app/node_modules/mquery/lib/mquery.js
2022-03-07T01:25:09.883382+00:00 app[web.1]: - /app/node_modules/mongoose/lib/promise_provider.js
2022-03-07T01:25:09.883382+00:00 app[web.1]: - /app/node_modules/mongoose/lib/helpers/promiseOrCallback.js
2022-03-07T01:25:09.883382+00:00 app[web.1]: - /app/node_modules/mongoose/lib/utils.js
2022-03-07T01:25:09.883382+00:00 app[web.1]: - /app/node_modules/mongoose/lib/statemachine.js
2022-03-07T01:25:09.883383+00:00 app[web.1]: - /app/node_modules/mongoose/lib/internal.js
2022-03-07T01:25:09.883383+00:00 app[web.1]: - /app/node_modules/mongoose/lib/document.js
2022-03-07T01:25:09.883383+00:00 app[web.1]: - /app/node_modules/mongoose/lib/index.js
2022-03-07T01:25:09.883383+00:00 app[web.1]: - /app/node_modules/mongoose/index.js
2022-03-07T01:25:09.883386+00:00 app[web.1]: - /app/db/connect.js
2022-03-07T01:25:09.883386+00:00 app[web.1]: - /app/app.js
2022-03-07T01:25:09.883387+00:00 app[web.1]: at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
2022-03-07T01:25:09.883387+00:00 app[web.1]: at Function.Module._load (node:internal/modules/cjs/loader:778:27)
2022-03-07T01:25:09.883388+00:00 app[web.1]: at Module.require (node:internal/modules/cjs/loader:1005:19)
2022-03-07T01:25:09.883388+00:00 app[web.1]: at require (node:internal/modules/cjs/helpers:102:18)
2022-03-07T01:25:09.883388+00:00 app[web.1]: at Object.<anonymous> (/app/node_modules/debug/src/node.js:240:18)
2022-03-07T01:25:09.883389+00:00 app[web.1]: at Module._compile (node:internal/modules/cjs/loader:1103:14)
2022-03-07T01:25:09.883389+00:00 app[web.1]: at Object.Module._extensions..js (node:internal/modules/cjs/loader:1155:10)
2022-03-07T01:25:09.883389+00:00 app[web.1]: at Module.load (node:internal/modules/cjs/loader:981:32)
2022-03-07T01:25:09.883390+00:00 app[web.1]: at Function.Module._load (node:internal/modules/cjs/loader:822:12)
2022-03-07T01:25:09.883390+00:00 app[web.1]: at Module.require (node:internal/modules/cjs/loader:1005:19) {
2022-03-07T01:25:09.883390+00:00 app[web.1]: code: 'MODULE_NOT_FOUND',
2022-03-07T01:25:09.883390+00:00 app[web.1]: requireStack: [
2022-03-07T01:25:09.883391+00:00 app[web.1]: '/app/node_modules/debug/src/node.js',
2022-03-07T01:25:09.883391+00:00 app[web.1]: '/app/node_modules/debug/src/index.js',
2022-03-07T01:25:09.883391+00:00 app[web.1]: '/app/node_modules/mquery/lib/mquery.js',
2022-03-07T01:25:09.883392+00:00 app[web.1]: '/app/node_modules/mongoose/lib/promise_provider.js',
2022-03-07T01:25:09.883392+00:00 app[web.1]: '/app/node_modules/mongoose/lib/helpers/promiseOrCallback.js',
2022-03-07T01:25:09.883393+00:00 app[web.1]: '/app/node_modules/mongoose/lib/utils.js',
2022-03-07T01:25:09.883393+00:00 app[web.1]: '/app/node_modules/mongoose/lib/statemachine.js',
2022-03-07T01:25:09.883393+00:00 app[web.1]: '/app/node_modules/mongoose/lib/internal.js',
2022-03-07T01:25:09.883393+00:00 app[web.1]: '/app/node_modules/mongoose/lib/document.js',
2022-03-07T01:25:09.883394+00:00 app[web.1]: '/app/node_modules/mongoose/lib/index.js',
2022-03-07T01:25:09.883394+00:00 app[web.1]: '/app/node_modules/mongoose/index.js',
2022-03-07T01:25:09.883394+00:00 app[web.1]: '/app/db/connect.js',
2022-03-07T01:25:09.883394+00:00 app[web.1]: '/app/app.js'
2022-03-07T01:25:09.883394+00:00 app[web.1]: ]
2022-03-07T01:25:09.883395+00:00 app[web.1]: }
2022-03-07T01:25:10.033008+00:00 heroku[web.1]: Process exited with status 1
2022-03-07T01:25:10.264584+00:00 heroku[web.1]: State changed from starting to crashed

I have installed the common package separately using npm install common --save, but that did not solve the issue. Also deleted node_modules and reinstalled all the modules. However nothing seems to work. I've scoured the internet for an answer to this, and haven't found anything yet that works.

My package.json looks like this,

{
  "name": "starter-again",
  "version": "1.0.0",
  "main": "app.js",
  "scripts": {
    "start": "node app.js"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "dotenv": "^16.0.0",
    "nodemon": "^2.0.15"
  },
  "dependencies": {
    "common": "^0.2.5",
    "debug": "^4.3.3",
    "express": "^4.17.3",
    "mongoose": "^6.2.4"
  },
  "engines": {
    "node": "16.14.0"
  },
}

Any suggestion on how to solve this error?

Answer 1

I solved this by not having node_modules in my .gitignore folder which was there originally.