SyntaxError: Cannot use import statement outside a module

What causes this

You’re using ES module syntax (import/export) in a file that Node.js treats as CommonJS. By default, Node.js treats .js files as CommonJS (which uses require()), not ES modules (which use import).

This also happens in:

• Jest tests that import ES module code
• TypeScript projects with wrong module settings
• Older Node.js versions that don’t fully support ES modules

Fix 1: Add “type”: “module” to package.json

Tell Node.js to treat all .js files as ES modules:

{
  "name": "my-project",
  "type": "module"
}

After this, import works in all .js files. If you have files that need CommonJS, rename them to .cjs.

Fix 2: Use the .mjs extension

If you don’t want to change the whole project, rename just the file using import:

mv app.js app.mjs
node app.mjs

.mjs files are always treated as ES modules regardless of package.json.

Fix 3: Use require() instead

If you want to stay in CommonJS:

// ❌ ES module syntax in CommonJS
import express from 'express';

// ✅ CommonJS syntax
const express = require('express');

For named exports:

// ❌ ES module
import { readFile } from 'fs/promises';

// ✅ CommonJS
const { readFile } = require('fs/promises');

Fix 4: Fix TypeScript configuration

If you’re using TypeScript, check your tsconfig.json:

{
  "compilerOptions": {
    "module": "commonjs",
    "esModuleInterop": true,
    "moduleResolution": "node"
  }
}

With "module": "commonjs", TypeScript compiles import statements to require() calls. If you want actual ES modules:

{
  "compilerOptions": {
    "module": "ESNext",
    "moduleResolution": "bundler"
  }
}

And add "type": "module" to package.json.

Fix 5: Fix Jest configuration

Jest runs in CommonJS by default. If your source code uses ES modules:

// package.json
{
  "jest": {
    "transform": {
      "^.+\\.(ts|tsx|js|jsx)$": "babel-jest"
    }
  }
}

Or use the experimental ESM support:

node --experimental-vm-modules node_modules/.bin/jest

A simpler alternative: switch to Vitest, which supports ES modules natively.

Fix 6: Dynamic import as a workaround

If you need to import an ES module from CommonJS code:

// CommonJS file that needs an ES module
async function main() {
  const { default: chalk } = await import('chalk');
  console.log(chalk.green('Hello'));
}
main();

How to prevent it

• Decide early: is your project CommonJS or ES modules? Set "type": "module" (or don’t) in package.json from the start
• For new projects, prefer ES modules — it’s the standard going forward
• If using TypeScript, make sure module in tsconfig.json matches your package.json type
• When mixing module systems is unavoidable, use .mjs for ES modules and .cjs for CommonJS