Error [ERR_REQUIRE_ESM]: require() of ES Module not supported

What causes this error

Node's CommonJS require() cannot synchronously load an ES Module. If a package's package.json declares "type": "module", or it only ships .mjs files, calling require('that-package') throws ERR_REQUIRE_ESM — even though import works fine for the same package.

The Fix

// Wrong — CommonJS file requiring an ESM-only package
const chalk = require('chalk'); // throws ERR_REQUIRE_ESM

// Fix 1: dynamic import (works from a CommonJS file too)
const { default: chalk } = await import('chalk');

// Fix 2: convert your own file/project to ESM
// package.json: "type": "module"
import chalk from 'chalk';

Common causes / variations

• Upgrading a dependency (chalk, node-fetch, execa, nanoid, etc.) to a major version that dropped CommonJS support entirely
• Mixing CommonJS (default for `.js`) and ESM-only packages in the same project without a migration plan
• Running TypeScript through a CommonJS-mode transpiler against an ESM-only dependency

Related errors

See also: Cannot find module (missing file extension in ESM), Unknown file extension ".ts".