Resolving Dependency Error in a Next.js 15 and Payload CMS 3 Project

If you’ve ever worked with modern JavaScript frameworks, you’ve probably encountered your fair share of dependency issues. In this post, I’ll walk you through the challenges I faced when combining Next.js 15 with Payload CMS 3, the errors that popped up, and how I ultimately resolved them by migrating from npm to pnpm.

The Setup

I started a new project using the following stack:

• Next.js 15 for a modern frontend framework.
• Payload CMS 3 to handle content management with its powerful admin panel.

Everything seemed fine initially, but when I tried to access the Payload admin panel and later generate type definitions for my collections, the errors began rolling in.

Error 1: React Version Mismatch

Payload CMS had a peer dependency on a newer React version, but my project was locked to React 18.3.1. This version mismatch prevented the admin panel from functioning.

Attempted Solution:

I tried deleting node_modules, .next & package-lock.json file and install dependecies again using npm i --legacy-peer-deps to bypass dependency checks. This command allowed npm to install conflicting dependencies, but I wasn’t confident this hacky workaround would hold up long-term.

Error 2: ESM vs. CommonJS Conflict

Next, I tried to generate type definitions for my Payload collections using npm run generate:types, instead of success, I encountered this error:

The database adapter @payloadcms/db-mongodb was distributed as an ES Module (ECMAScript Module), but something in my setup (likely the type generation script) was trying to use it with CommonJS syntax. This mismatch caused Node.js to throw an error.

The Solution: Migrating to pnpm

After hours of debugging and trying to resolve each error manually, I decided to migrate my project from npm to pnpm. Surprisingly, this one change resolved all the issues!

Why pnpm Works Better:

• Better Dependency Management: pnpm uses a unique structure for dependencies, which avoids many conflicts that npm struggles with.
• Efficient Peer Dependency Handling: Instead of forcing you to choose between strict version constraints and bypassing them entirely, pnpm resolves peer dependencies in a more balanced way.
• Strict Yet Flexible: By default, pnpm enforces strict version rules, helping avoid errors caused by dependency mismatch or improper resolutions.

To migrate to pnpm, I followed these steps:

1. Removed the existing node_modules folder:

rm -rf node_modules package-lock.json

1. Installed dependencies using pnpm:

pnpm install

Once the migration was complete, both the React version mismatch and the ESM-related errors disappeared. The Payload admin panel worked flawlessly, and type generation executed without a hitch.

Key Takeaways

1. React Version Compatibility: Always check compatibility between frameworks and libraries before starting a project. Payload CMS 3 required a newer React version that wasn’t aligned with Next.js 15’s default setup.

2. ESM vs. CommonJS Conflicts: Node.js now heavily favors ESM modules. If a library is distributed as ESM, ensure your project is configured to handle it properly, or use tools like pnpm to resolve the mismatch.

3. Why Choose pnpm Over npm: For projects with complex dependencies, pnpm can save you from countless hours of debugging by managing dependencies more efficiently.

Final Thoughts

Switching to pnpm felt like a game-changer for my project. It not only resolved the issues but also gave me peace of mind knowing my dependencies were better managed. If you’re struggling with dependency issues or module conflicts in your project, consider giving pnpm a try. It might just be the solution you need!