Fix ERR_REQUIRE_CYCLE_MODULE Error in Node.js (2025 Guide)

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If you’ve encountered the “Error [ERR_REQUIRE_CYCLE_CYCLE_MODULE]: Cannot require() ES Module” in Node.js, you’re not alone. This error can feel like a cryptic roadblock, especially when you’re certain you’re not even using ES Modules. It pops up when Node.js detects a circular dependency or a mismatch between CommonJS and ES Module systems. In this guide, we’ll break down why this error happens, how to fix it, and how to prevent it in the future—whether you’re a beginner or a seasoned developer.

We’ll dive into the root causes, provide step-by-step solutions with real-world examples, and share tips to keep your Node.js projects error-free. By the end, you’ll have a clear understanding of this error and the confidence to tackle it. Let’s get started!

What Is the [ERR_REQUIRE_CYCLE_MODULE] Error?

The ERR_REQUIRE_CYCLE_MODULE error occurs in Node.js when there’s a circular dependency between modules or when Node.js misinterprets a file as an ES Module (ESM) while you’re using CommonJS. Circular dependencies happen when two or more modules try to require() each other, creating a loop. Alternatively, Node.js might throw this error if it expects an ES Module (.mjs file or "type": "module" in package.json) but encounters CommonJS syntax (e.g., require()).

For example, imagine you’re building a simple Node.js app, and you see this error:

Error [ERR_REQUIRE_CYCLE_MODULE]: Cannot require() ES Module. require() of /path/to/your/file.js from /path/to/another/file.js is an ES Module

This message is confusing because you might not even be using ES Modules. Let’s explore why this happens and how to fix it.

Why Does This Error Happen?

Here are the most common causes of the ERR_REQUIRE_CYCLE_MODULE error:

  • Circular Dependencies: Module A requires Module B, and Module B requires Module A, creating a loop that Node.js can’t resolve.
  • Mixed Module Systems: You’re using require() (CommonJS) in a project configured for ES Modules, or vice versa.
  • Incorrect File Extensions: Using .js instead of .mjs (or vice versa) when Node.js expects a specific module type.
  • Misconfigured package.json: The "type": "module" field in package.json tells Node.js to treat .js files as ES Modules, which conflicts with CommonJS syntax.
  • Dynamic Imports Gone Wrong: Incorrect use of import() or mixing static and dynamic imports in a way that confuses Node.js.

Understanding the cause is the first step to fixing the error. Let’s break down each scenario and provide solutions.

How to Fix the [ERR_REQUIRE_CYCLE_MODULE] Error

Let’s walk through actionable solutions for each cause of the error. We’ll use examples to make the process clear and include code snippets you can apply to your projects.

1. Resolve Circular Dependencies

Circular dependencies are a common culprit. They occur when modules depend on each other in a loop. For example:

Example of a Circular Dependency:

// file: user.js
const order = require('./order');
module.exports = {
  getUser: () => 'User Data',
  getOrder: () => order.getOrder(),
};

// file: order.js
const user = require('./user');
module.exports = {
  getOrder: () => 'Order Data',
  getUser: () => user.getUser(),
};

Here, user.js requires order.js, and order.js requires user.js, creating a loop. Node.js throws the ERR_REQUIRE_CYCLE_MODULE error because it can’t resolve this dependency chain.

Solution: Restructure Your Code

To fix this, refactor your code to eliminate the circular dependency. Here are two approaches:

  • Move Shared Logic to a Third Module: Create a new module (e.g., utils.js) to hold shared functionality that both user.js and order.js need.
// file: utils.js
module.exports = {
  sharedFunction: () => 'Shared Data',
};

// file: user.js
const utils = require('./utils');
module.exports = {
  getUser: () => 'User Data',
  getShared: () => utils.sharedFunction(),
};

// file: order.js
const utils = require('./utils');
module.exports = {
  getOrder: () => 'Order Data',
  getShared: () => utils.sharedFunction(),
};
  • Delay the require Statement: Move the require call inside a function to delay its execution until the module is fully loaded.
// file: user.js
module.exports = {
  getUser: () => 'User Data',
  getOrder: () => {
    const order = require('./order');
    return order.getOrder();
  },
};

This approach breaks the circular dependency by ensuring require is called only when needed.

2. Fix Mixed Module Systems

If your project mixes CommonJS (require, module.exports) and ES Modules (import, export), Node.js might throw the ERR_REQUIRE_CYCLE_MODULE error. This often happens if your package.json has "type": "module", but your code uses require().

Solution: Standardize Your Module System

  • Check Your package.json: Open your package.json file and look for the "type" field:
    • "type": "module": All .js files are treated as ES Modules.
    • "type": "commonjs" (or no "type" field): All .js files are treated as CommonJS.
    If you’re using CommonJS but see "type": "module", either remove the field or set it to "type": "commonjs".
{
  "type": "commonjs"
}
  • Convert to ES Modules: If you want to use ES Modules, update your code to use import and export syntax:
// file: user.mjs
import { getOrder } from './order.mjs';
export const getUser = () => 'User Data';
  • Use .mjs or .cjs Extensions: Explicitly indicate the module type by using .mjs for ES Modules or .cjs for CommonJS:
// file: user.cjs
const order = require('./order.cjs');
module.exports = {
  getUser: () => 'User Data',
};

3. Correct File Extensions

Node.js relies on file extensions to determine module types. If you’re using .js files but Node.js expects .mjs, you’ll get the ERR_REQUIRE_CYCLE_MODULE error.

Solution: Use the Correct Extension

  • For ES Modules, use .mjs or set "type": "module" in package.json.
  • For CommonJS, use .cjs or ensure "type": "commonjs" (or no "type" field).

Example:

// file: user.mjs (ES Module)
import { getOrder } from './order.mjs';
export const getUser = () => 'User Data';

// file: user.cjs (CommonJS)
const order = require('./order.cjs');
module.exports = {
  getUser: () => 'User Data',
};

4. Fix Dynamic Imports

Dynamic import() statements can sometimes cause this error if used incorrectly. For example, mixing require() and import() in the same module can confuse Node.js.

Solution: Use Consistent Import Syntax

If you’re using dynamic imports, ensure they align with your module system:

// For ES Modules
const module = await import('./module.mjs');

// For CommonJS
const module = require('./module.cjs');

If you need to mix module types, use dynamic imports for ES Modules in a CommonJS project:

// file: user.cjs
async function loadModule() {
  const module = await import('./module.mjs');
  return module.default;
}

5. Debugging Tips for Persistent Errors

If the above solutions don’t resolve the error, try these debugging steps:

  • Check Node.js Version: Ensure you’re using a compatible Node.js version. ES Modules are fully supported in Node.js 12.x and later.
  • Inspect Dependency Graph: Use tools like madge to detect circular dependencies:npm install -g madge madge --circular src/
  • Clear Cache: Clear the Node.js module cache to rule out stale dependencies:node --clear-cache your-script.js
  • Review Stack Trace: The error message includes a stack trace pointing to the problematic files. Review it to identify the modules involved.

Best Practices to Avoid the Error

To prevent the ERR_REQUIRE_CYCLE_MODULE error in future projects, follow these best practices:

  • Organize Your Codebase: Structure your project to minimize dependencies between modules. Use a clear hierarchy (e.g., utilities, services, controllers).
  • Choose One Module System: Stick to either CommonJS or ES Modules throughout your project to avoid conflicts.
  • Use Linters: Tools like ESLint can detect potential circular dependencies during development.
  • Test Incrementally: Test your code after adding new modules to catch issues early.
  • Document Dependencies: Keep a record of how modules interact to avoid unintentional circular references.

Real-World Example: Fixing a Node.js App

Let’s say you’re building a small e-commerce app with two modules: product.js and cart.js. You encounter the ERR_REQUIRE_CYCLE_MODULE error because product.js requires cart.js, and vice versa.

Original Code (Problematic):

// file: product.js
const cart = require('./cart.js');
module.exports = {
  getProduct: () => 'Product Data',
  addToCart: () => cart.addItem(),
};

// file: cart.js
const product = require('./product.js');
module.exports = {
  addItem: () => 'Item Added',
  getProduct: () => product.getProduct(),
};

Fixed Code:

// file: utils.js
module.exports = {
  sharedLogic: () => 'Shared Data',
};

// file: product.js
const utils = require('./utils.js');
module.exports = {
  getProduct: () => 'Product Data',
  addToCart: () => utils.sharedLogic(),
};

// file: cart.js
const utils = require('./utils.js');
module.exports = {
  addItem: () => 'Item Added',
  getShared: () => utils.sharedLogic(),
};

By moving shared logic to utils.js, you eliminate the circular dependency and resolve the error.

FAQs About the [ERR_REQUIRE_CYCLE_MODULE] Error

What does the [ERR_REQUIRE_CYCLE_MODULE] error mean?

This error indicates a circular dependency between modules or a mismatch between CommonJS and ES Module systems in Node.js.

Can I mix CommonJS and ES Modules in the same project?

Yes, but you need to be careful. Use .mjs for ES Modules and .cjs for CommonJS, or use dynamic imports to bridge the two systems.

How do I know if I’m using ES Modules?

Check your package.json for "type": "module", or look for .mjs files or import/export syntax in your code.

What tools can help detect circular dependencies?

Tools like madge or ESLint can identify circular dependencies in your codebase.

Is this error specific to a Node.js version?

The error is more common in Node.js 12.x and later, when ES Module support was introduced. Ensure your Node.js version supports your module system.

Summary: Tackle the Error with Confidence

The “Error [ERR_REQUIRE_CYCLE_MODULE]: Cannot require() ES Module” can be frustrating, but it’s manageable with the right approach. By identifying whether the issue stems from circular dependencies, mixed module systems, or incorrect file extensions, you can apply targeted fixes like refactoring code, standardizing module types, or using proper extensions. Tools like madge and clear project organization can prevent this error from recurring.

For more Node.js tips and troubleshooting, check out the official Node.js documentation or explore community resources on platforms like Stack Overflow.

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