Cannot find module 'express' or 'cors' error in Node.js

# Table of Contents

1. Cannot find module 'EXPRESS' error in Node.js
2. Cannot find module 'CORS' error in Node.js

# Cannot find module 'express' error in Node.js

To solve the error "Cannot find module 'express'", install the package by running the command npm install express in the root directory of your project.

If you don't have a package.json file, create one by running npm init -y.

If you got the error "Cannot find module 'cors'", click on the following subheading.

The error occurs when we try to import the express package without installing it.

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// ⛔️ Cannot find module 'express'
//  Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'express'
// imported from bobbyhadz-js/index.js
import express from 'express';

const app = express();
const port = 3445;

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`);
});

Make sure you have express installed by opening your terminal in your project's root directory (the one that contains your package.json file) and running the following command:

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npm install express

# 👇️ Only if you use TypeScript
npm install @types/express --save-dev

If your project doesn't have a package.json file, you have to initialize one in your project's root directory.

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# Create package.json file (if you don't have one)
npm init -y

npm install express

# 👇️ Only if you use TypeScript
npm install @types/express --save-dev

Once you have express installed, the error should be resolved.

# Delete node_modules and reinstall your packages

If the error is not resolved, try to delete your node_modules directory and the package-lock.json file, re-run npm install and restart your IDE if necessary.

Open your terminal in your project's root directory and run the following commands.

If you are on macOS or Linux, issue the following commands in bash or zsh.

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#  for macOS and Linux
rm -rf node_modules
rm -f package-lock.json
rm -f yarn.lock

# 👇️ clean your npm cache
npm cache clean --force

# 👇️ install packages
npm install

If you are on Windows, issue the following commands in CMD.

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# for Windows
rd /s /q "node_modules"
del package-lock.json
del -f yarn.lock

# 👇️ clean your npm cache
npm cache clean --force

# 👇️ install packages
npm install

Make sure to restart your IDE if the error persists. VSCode often glitches and needs a reboot.

If you get any errors when running these commands, try to manually delete the node_modules and package-lock.json files from your project's root directory.

If you get a permissions error, try re-running the command with sudo, e.g. sudo npm install.

Now you should be able to import and use the express package.

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import express from 'express';

const app = express();
const port = 3445;

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`);
});

# Check if express is contained in your dependencies

If the error persists, open your package.json file and make sure it contains the express package in the dependencies object.

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{
  // ....
  "dependencies": {
    "express": "^4.17.3",
    // ....
  },
}

You can try to manually add the line and re-run npm install.

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npm install

# Cannot find module 'cors' error in Node.js

To solve the error "Cannot find module 'cors'", make sure to install the cors package by opening your terminal in your project's root directory and running the following command: npm i cors.

If you use TypeScript, install the typings by running npm i -D @types/cors.

Here is an example of how the error occurs.

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// ⛔️ Error Cannot find module 'cors'
// [ERR_MODULE_NOT_FOUND]: Cannot find package 'cors'
// imported from bobbyhadz-js/index.js
const express = require('express');
const cors = require('cors');

const app = express();

app.use(cors());

app.get('/products/:id', function (req, res, next) {
  res.json({msg: 'This is CORS-enabled for all origins!'});
});

app.listen(1234, function () {
  console.log('CORS-enabled web server listening on port 1234');
});

Open your terminal in your project's root directory (where your package.json file is located) and run the following commands:

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npm install cors

# 👇️ only if you use TypeScript
npm install --save-dev @types/cors

This will add the cors package to the dependencies of your project.

# Delete your node_modules and reinstall your dependencies

If the error is not resolved, try to delete your node_modules and package-lock.json (not package.json) files, re-run npm install and restart your IDE.

If you are on macOS or Linux, issue the following commands in bash or zsh.

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#  for macOS and Linux
rm -rf node_modules
rm -f package-lock.json
rm -f yarn.lock

# 👇️ clean your npm cache
npm cache clean --force

# 👇️ install packages
npm install

If you are on Windows, issue the following commands in CMD.

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# for Windows
rd /s /q "node_modules"
del package-lock.json
del -f yarn.lock

# 👇️ clean your npm cache
npm cache clean --force

# 👇️ install packages
npm install

If you use TypeScript and get the error "Cannot find module 'cors' or its corresponding type declarations", run npm install --save-dev @types/cors and make sure the types array contains the string node.

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{
  "compilerOptions": {
    "types": [
      "node"
    ]
  },
}

# Verify the cors package is in your dependencies object

If you still get the "Cannot find module 'cors'" error, open your package.json file and make sure it contains the cors package in the dependencies object.

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{
  // ... rest
  "dependencies": {
    "cors": "^2.8.5",
  },
  "devDependencies": {
    // 👇️ only if you use TypeScript
    "@types/cors": "^2.8.12",
  }
}

You can try to manually add the line and re-run npm install.

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npm install

Or install the latest version of the package:

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npm install cors@latest

npm install --save-dev @types/cors@latest