Why I'm getting Error [ERR_MODULE_NOT_FOUND]: Cannot find module when running the server

Question

I'm doing a startup server. Basically It has initial setup with express and nodemon dependencies. Unfortunately, I'm getting ERR_MODULE_NOT_FOUND when running yarn dev or npm run dev Here is the code and file structure I have.

Answer 1

You need to add.js extension index.js:

import { SampleExport } from "../path/file.js"

In my opinion, it is better to use.env files together with some npm package or even a json file.

Answer 2

Nodemon is developer dependency you need to do these commands:

npm uninstall --save nodemon
npm install --save-dev nodemon

Answer 3

Instead of using export itself you should use module.exports = someFuncName in your env.js file. export not working and js can not require your function or something...

Answer 4

The issue is a missing file extension. The import needs to look like this:

import { sampleExport } from "../config/env.js";
//                                         ^^^

import doesn't use the same algorithm that require used. Instead, it works according to the ECMAScript Modules specification, which requires a definite extension.

This is also explained in the node.js docs for ECMAScript modules :

A file extension must be provided when using the import keyword to resolve relative or absolute specifiers. Directory indexes (eg './startup/index.js' ) must also be fully specified.

This behavior matches how import behaves in browser environments, assuming a typically configured server.