Hello JavaScript Enthusiasts!
Welcome to a new edition of "This Week in JavaScript"!
This week, we’re hyped about Cursor 1.0’s release and how it might make VS Code obsolete, Rolldown’s lightning-fast Vite builds, TC39’s bold JavaScript advancements, and WebStatus.dev’s game-changing web insights. As always, we’ll also talk about some powerful tools to elevate your development workflow.
Forget VS Code, Cursor 1.0 Is Finally Here
Cursor 1.0 has landed, bringing AI-driven coding to new heights with BugBot for automated pull request reviews, Background Agent for remote coding tasks, Memories for contextual intelligence, Jupyter Notebook integration, and one-click MCP setup. It’s a must-have for JavaScript devs looking to automate and accelerate their workflows.
- BugBot enhances code quality by automatically reviewing pull requests on GitHub, identifying bugs and potential issues, and providing detailed comments. It includes a “Fix in Cursor” button that directs you to your editor with a pre-filled prompt to address the issue.
- Background Agent enables developers to execute remote coding tasks efficiently. You can activate it using Cmd/Ctrl+E or the cloud icon in the chat interface. If you enable privacy mode, Cursor will soon provide full support to ensure secure workflows. Developers who adopted Background Agent early praised its efficiency, and now all users can utilize it to generate React components or optimize Node.js APIs.
- Memories, currently in beta, transforms how Cursor understands your projects by storing project-specific facts for each user and project. You can manage these facts through Settings → Rules, allowing Cursor to recall details like your preferred state management approach, which results in more accurate suggestions.
- For data science professionals, Cursor’s Jupyter Notebook support allows the Agent to create and edit multiple cells directly, significantly improving productivity. This feature, available only with Sonnet models, makes Cursor ideal for crafting JavaScript-driven data visualizations or machine learning pipelines.
- Cursor simplifies server authentication with one-click MCP installations and OAuth support. A curated list of official MCP servers is available at docs.cursor.com. The chat interface now supports richer responses, the redesigned Settings and Dashboard provide a polished user experience, offering analytics on tool and model usage, which helps teams optimize their workflows.
This JavaScript Bundler Is FAST AF
Rolldown, a next-generation bundler built in Rust, is revolutionizing the core of Vite. The rolldown-vite package serves as a drop-in replacement for Vite, delivering exceptional performance improvements for JavaScript applications. As a technical preview, Rolldown leverages Oxc, a high-performance JavaScript toolkit that handles parsing, transforming, resolving, and minifying, setting new benchmarks for speed and efficiency.
- By replacing Vite’s dependency on esbuild with Oxc, Rolldown achieves build time reductions ranging from 3 to 16 times faster and reduces memory usage by up to one hundred times. For example GitLab’s build time decreased from 2.5 minutes to 40 seconds, Excalidraw’s from 22.9 seconds to 1.4 seconds, Appwrite’s from over 12 minutes to 3 minutes, and Particl’s from over a minute to 6 seconds, outperforming Vite by nearly ten times and Next.js by twenty-nine times. Even this blog post, built using VitePress with Rolldown Vite, completed in just 1.8 seconds on Netlify. To integrate Rolldown Vite, you can alias Vite in your package.json:
{
"dependencies": {
"vite": "npm:rolldown-vite@latest"
}
}
- For projects using VitePress or meta-frameworks, you can use overrides to replace vite with rolldown-vite. Most Vite plugins and frameworks are compatible, though some incompatibilities exist, which you can review in the migration guide. As a standalone package, rolldown-vite allows rapid iteration, though patch versions may introduce breaking changes, which are documented in its changelog. Once stabilized, Rolldown will integrate into Vite’s main codebase, phasing out the separate package.
- Rolldown Vite is a must-try for developers building performance-critical JavaScript applications.
Upcoming JavaScript Features From TC39
The 108th TC39 meeting advanced nine JavaScript proposals, with three,Array.fromAsync, Error.isError, and Explicit Resource Management,reaching Stage 4, positioning them for inclusion in the ECMAScript specification. These developments enhance JavaScript’s capabilities for asynchronous workflows and resource management.
- The Array.fromAsync proposal, simplifies the handling of asynchronous iterables, eliminating the need for manual for await...of loops. It serves as a native alternative to libraries like it-all, which sees 50,000 weekly downloads, and supports asynchronous iterables, synchronous iterables with promises, and array-like objects.
- For example:
async function* asyncGen(n) { for (let i = 0; i < n; i++) yield i * 2; }
const arr = await Array.fromAsync(asyncGen(4)); // [0, 2, 4, 6]
This feature is particularly valuable for unit tests, command-line applications, or streaming data processing in Node.js, offering optional mapfn and thisArg parameters for added flexibility.
- The Error.isError proposal, introduces a reliable method for detecting errors across different realms, resolving inconsistencies with instanceof Error in environments like iframes or Node.js virtual machines. This improvement is crucial for debugging, serialization tasks in platforms like RunKit, or structured cloning operations.
- The Explicit Resource Management proposal, introduces using and await using declarations, supported by DisposableStack and AsyncDisposableStack, to ensure deterministic cleanup of resources such as file handles, streams, or locks. Inspired by C#’s using and Python’s with statements, it reduces boilerplate code significantly.
- For instance:
using handle = acquireFileHandle(); // Automatically disposes at block end
const stack = new DisposableStack(); // Manages multiple resources
stack.use(resource1); stack.use(resource2); // Ensures reverse-order cleanup
- This approach mitigates common errors, such as omitting try/finally blocks or mismanaging multiple resources, in Node.js applications that handle files or streams. These advancements collectively empower JavaScript developers to build robust asynchronous APIs and resource-intensive systems.
The Ultimate Web Platform Dashboard
WebStatus.dev has undergone a massive evolution, now tracking over 1000 web platform features,nearly 100% coverage,with mobile browser data, usage timelines, and deep insights to guide JavaScript apps toward Baseline interoperability. It’s an indispensable tool for front-end developers.
- Sourced from the W3C’s web-features project, involving all major browser vendors, WebStatus.dev provides Chrome usage data since 2012, complete with adoption timelines for nearly all features.
- Mobile browser support highlights Baseline gaps, enabling smarter progressive enhancement strategies for React or Vue apps. Powerful sorting and filtering let you query specific scenarios, like API landing in Safari in the last 12 months that were already in Chrome and Firefox, sorted by usage. Shareable dashboards streamline team workflows, letting you create custom views for Web UI APIs or project-specific needs.
- This helps devs like you plan adoption of cutting-edge APIs. WebStatus is a must for building cross-browser JavaScript apps with confidence.
Tools & Releases You Should Know About
- @platformatic/php-node: This innovative Node.js runtime seamlessly integrates PHP into your Node.js applications, allowing PHP to function as a high-performance request processor. Developed using Rust and napi.rs, it employs a language-agnostic lang_handler system to route requests to multi-threaded PHP workers within Node.js’s worker pool, significantly reducing latency by eliminating network calls.This tool is perfect for developers who seek a unified development environment for JavaScript and PHP, simplifying workflows and boosting application performance.
- Starry Night v3.8: This open-source syntax highlighter replicates the functionality of GitHub’s closed-source PrettyLights, supporting over 600 programming languages with TextMate grammars, which deliver exceptional quality, as used in editors like VS Code, SublimeText, and Atom. Starry Night generates abstract syntax trees (ASTs) for versatile rendering, such as ANSI sequences for command-line interfaces or React/Preact for virtual DOM applications, and supports CSS-driven themes for effortless dark mode integration. Unlike shiki, which uses inline styles, Starry Night’s CSS class-based approach simplifies theming, making it a top choice for developers building code-rich platforms.
- ngx-vflow: This Angular library empowers developers to create node-based applications, ranging from static diagrams to fully interactive visual editors. Built on Angular signals for outstanding performance, ngx-vflow simplifies complex interactions like dragging, zooming, and curve rendering through an intuitive API. Whether you are visualizing JavaScript application architectures or debugging Angular-based pipelines, ngx-vflow provides robust, scalable solutions for building interactive development tools.
- Docusaurus 3.8: This powerful React-based documentation platform boosts build performance with Docusaurus Faster, leveraging Rspack’s persistent cache and Node.js worker threads for 2–5x faster rebuilds and 2x quicker static site generation. New Future Flags prepare your site for Docusaurus 4, while optimizations like SVG sprites and macOS startup tweaks enhance efficiency. Perfect for JavaScript devs crafting sleek, high-performance documentation sites for React or Node.js projects.
And that's it for the thirty-eighth issue of "This Week in JavaScript."
Feel free to share this newsletter with a fellow developer, and make sure you're following for more weekly updates.
Until next time, happy coding!