1. Introduction of the Permission Model
2. Improvements to the ESM (ECMAScript Modules) loader hooks
3. Updated V8 engine to version 11.3
4. Official support for ARM64 Windows
5. The latest version of the URL parser, Ada 2.0
6. Test_runner module marked as stable
7. Deprecations and Removals
8. Conclusion

Node.js, the popular open-source, cross-platform JavaScript runtime environment, has released version 20 with several exciting features and updates.

One of the most significant additions is the experimental Permission Model, which restricts access to specific resources during program execution. The ESM loader hooks now run on a dedicated thread to ensure no cross-contamination between loaders and application code. The V8 engine has been updated to version 11.3, which includes three new features to the JavaScript API. Additionally, the URL parser Ada 2.0 brings significant performance improvements to URL parsing. Node.js 20 also includes official support for ARM64 Windows. Several deprecations and removals are included, such as the runtime deprecation of url.parse() with invalid ports.

In this blog, we will take a closer look at some of the notable changes and additions to Node.js.

Introduction of the Permission Model

• Enables developers to restrict access to specific resources during program execution
• Prevents applications from accessing or modifying sensitive data or running potentially harmful code
• Enabled by using the --experimental-permission flag
• Contributed by Rafael Gonzaga

Improvements to the ESM (ECMAScript Modules) loader hooks

• ESM hooks supplied via loaders now run in a dedicated thread, isolated from the main thread
• Provides a separate scope for loaders and ensures no cross-contamination between loaders and application code
• import.meta.resolve() now returns synchronously, providing better alignment with browser behavior
• Contributed by Anna Henningsen, Antoine du Hamel, Geoffrey Booth, Guy Bedford, Jacob Smith, and Michaël Zasso

Updated V8 engine to version 11.3

• Includes three new features to the JavaScript API: String.prototype.isWellFormed and toWellFormed, resizable ArrayBuffer and growable SharedArrayBuffer, and WebAssembly Tail Call
• RegExp v flag with set notation + properties of strings have been added
• Contributed by Michaël Zasso

Official support for ARM64 Windows

• Allows for native execution on the platform
• The MSI, zip/7z packages, and executable are available from the Node.js download site
• The CI system was updated, and all changes are now fully tested on ARM64 Windows to prevent regressions and ensure compatibility
• Contributed by Stefan Stojanovic

The latest version of the URL parser, Ada 2.0

• Brings significant performance improvements to the URL parsing
• Enhancements to the url.domainToASCII and url.domainToUnicode functions in node:url
• Ada 2.0 has been integrated into the Node.js codebase
• Features a significant performance boost over its predecessor, Ada 1.0.4, while also eliminating the need for the ICU requirement for URL hostname parsing
• Contributed by Yagiz Nizipli and Daniel Lemire

Test_runner module marked as stable

• Previously experimental, now stable and ready for production use
• Contributed by Colin Ihrig

Deprecations and Removals

• Runtime-deprecation of url.parse() with invalid ports
• These URLs will emit a warning, and in future versions, they will throw an error, as the WHATWG URL API already does
• Contributed by Rich Trott

Conclusion

Overall, Node.js version 20 comes with several notable changes and improvements that make it more stable and efficient. Developers can take advantage of the experimental Permission Model feature, the Custom ESM loader hooks running on a dedicated thread, and the updated V8 engine with several new features to the JavaScript API. Other notable changes include the stable test runner module, the latest version of the URL parser Ada 2.0, official support for ARM64 Windows, and the requirement to specify the WASI version.

It is recommended to carefully review the release notes before upgrading to ensure compatibility with existing code.