2 minutes
Adopting Pure ESM Packages: A Guide for JavaScript Developers
As JavaScript evolves, ECMAScript Modules (ESM) have become the standard, offering benefits like improved performance, strict mode by default, and better compatibility across environments. Transitioning to ESM, however, requires careful adjustments, particularly for projects that rely on CommonJS.
Why Move to ESM?
Switching to ESM offers a cleaner, more modern syntax and optimizes compatibility with the latest tools. Node.js and other platforms are increasingly favoring ESM, making it necessary for packages to adapt.
Steps to Convert to ESM
- Update Package.json: Declare
"type": "module"
to ensure Node.js treats files as ESM. - Convert Imports: Replace
require()
withimport
statements. This includes rethinking exports; useexport
directly instead ofmodule.exports
. - Adjust TypeScript Configuration: TypeScript now supports ESM natively, but ensure your configurations (like
module
andtarget
intsconfig.json
) align with ESM requirements. - Test Compatibility: Ensure your ESM package works seamlessly with various environments, including Electron and build tools that support or require ESM. Testing can reveal any lingering issues that may stem from dependency compatibility or legacy tool configurations.
Addressing Common Issues
Some packages and tools may not yet fully support ESM. In these cases, consider using conditional exports or dual-package structures for compatibility. This allows backward compatibility while benefiting from the latest module format.
Final Thoughts
Converting to pure ESM can be a complex yet rewarding endeavor, bringing performance benefits and aligning with JavaScript’s future. If you’re ready to make the switch, careful planning and testing can make the transition smoother.