June 18, 2025

Subject: Exploring JS ES2025; fixing import map limitations; Node v24.2.0; Jest 30; Rstest testing framework; Oxlint 1.0; ESLint for DSLs; ESLint v9.29.0

Exploring JavaScript ES2025 edition

exploringjs.com @rauschma@fosstodon.org

A new edition of the book “Exploring JavaScript” by Axel is out:
  • Free to read online.
  • Lots of new and rewritten content (changelog)
  • Many new test-driven exercises (changelog)
  • New flashcards (in Anki and HTML format) help with learning the book’s content and JavaScript’s standard library.

Resilient import maps: fixing their limitations

shopify.engineering @Yoav@mastodon.social github.com/Shopify

“Import maps are great for both performance and developer experience, but their original limitations made them hard to use, especially at Shopify’s scale. We stepped up and pushed changes across the HTML spec, Chromium and WebKit to fix these issues at the web platform level. Now, developers can interleave JavaScript modules and multiple import maps on their HTML pages without worrying about correctness issues.”

Node v24.2.0 (current): import.meta.main and more

nodejs.org github.com/aduh95 @nodejs@social.lfx.dev

Testing tools

Jest 30: improved ESM support and more

jestjs.io github.com/MillerSvt github.com/cpojer

“Today we are happy to announce the release of Jest 30. This release features a substantial number of changes, fixes, and improvements. While it is one of the largest major releases of Jest ever, we admit that three years for a major release is too long. In the future, we are aiming to make more frequent major releases to keep Jest great for the next decade.”

Highlights:

  • Improved ECMAScript Module & TypeScript Support
  • Spies and the using keyword
  • expect.arrayOf
  • New test.each placeholder: %$
  • jest.advanceTimersToNextFrame()
  • Configurable test retries
  • jest.unstable_unmockModule()
  • jest.onGenerateMock(callback)
  • Custom object serialization

Rstest: Rspack-based testing framework

rstest.rs github.com/web-infra-dev

Linting tools

Announcing Oxlint 1.0

voidzero.dev github.com/Boshen github.com/camc314

“The first stable version Oxlint has been released! With a 50~100× performance improvement over ESLint, support for over 500 ESLint rules, and usage in major companies like Shopify, Airbnb, and Mercedes-Benz [...]”

How ESLint language plugins enhance DSL usability

eslint.org @nzakas@fosstodon.org @eslint@fosstodon.org

“If you’ve built a domain-specific language (DSL), the challenge goes beyond defining syntax. You also need to make the language easy and efficient to use. Without a familiar developer experience, even the most powerful DSLs can struggle to gain traction. ESLint language plugins offer a simple and effective way to provide guidance, enforce consistency, and improve usability from the start.”

ESLint v9.29.0: support for explicit resource management (using) and more

eslint.org github.com/mdjermanovic @eslint@fosstodon.org

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