Hi folks, in this Talk we learn about React and Chrome DevTools. We explore the new AI Assistant panel in DevTools that helps with UI tweaking. React DevTools now supports Gemini AI model for error fixing. Extensibility is important and React DevTools has features like highlight updates and server components. We also learn about server logging in the browser console and toggling suspense fallbacks. Browser DevTools allow experimenting with local overrides and improving color contrast. Advanced features include overriding headers, network panel customization, and performance tooling. We also discuss Core Web Vitals, optimizing pages, and debugging UI with DevTools. There are fun tips for enhancing animations and logging workflow. The Talk ends with Q&A and sharing/removing features based on user feedback.

The Talk delves into motion control with multimodal AI, exploring TensorFlow.js models for gesture recognition and enhancing user interactions. It discusses leveraging LLMs for gesture-based interaction, investigating Gemiini for gesture recognition, and controlling light states with Gemini functions. The conversation includes webcam-based gesture recognition, custom gesture databases, and the future of personalized AI assistance with acoustic recognition.

We asked co-sponsors to present React, an essential framework for web and mobile developers. TypeScript improves the development experience. Let's talk about the neglected topic of JavaScript leaks and how Chrome handles them. Leaks are easy to create, even for good developers. We crashed browsers due to memory leaks. Solution: fully reload the page after soft navigations. Today we have tools to fix leaks. The first step is admitting you have a problem. Use the reporting API to collect data on memory leaks. If you have a problem, it's not just a single leak. Debug and take memory snapshots. Load the page, perform an action, go back. Compare snapshots to find leaks. Use Memlab by Facebook to identify leaked objects. Memlab tells us memory is used, leaks are everywhere. Chrome extension helps with exporting actions to scenario.js file. 50 users already. Fixing memory leaks involves finding and nullifying unused objects. Spot the leak in a simple React component that adds event listeners. Removing the component leaves the listeners behind. In session two, adding a set interval creates additional listeners. Debugging with Memlab and using non-minified code and named functions helps identify the leaks. Solution: add a component. In React, frameworks provide ways to clean up after components are removed. Spotting a leak in uppercase spelling of mount. Hooks offer use effect to handle cleanup. A use effect allows you to return a function for cleanup. Spot the weird memory leak caused by console logs. Try the reporting API, check your framework, use null, and find your first leak. Memory leaks may be more significant on a mobile browser due to limited available memory. Differentiating between leaked memory and growing global state can be determined by the app's architecture. Checking for memory leaks on mobile can be done using dev tools and manual inspection or by using Puppeteer and the developer tools protocol for emulation. The lack of naming and bindings for anonymous functions in a codemark plugin is a potential area for improvement. Neglect and the excessive amount of JavaScript are common culprits for poor web performance. Facebook's experience with redesigning their website highlighted the need for tools to address the performance bottleneck caused by JavaScript. Throttling the CPU can be effective. Developers should set objects to null when they are no longer needed, allowing the garbage collector to clean up. Chrome DevTools provides options for detecting console log memory objects. WeakRefs and WeakMaps can be useful for cleaning up memory leaks. Integration with tools like MemLab can help regression test releases for memory leaks. We are still early in memory leaks tooling. Raising awareness about the problem is important. Lighthouse scores are not the sole indicator of a fast website. Additional testing and familiarity with Core Web Vitals are recommended.

Today, Wes Boss introduces the new features of the web, including customizable select and temporal, a standardized API for working with dates, time, and duration. The current date API in JavaScript has some problems related to time zones and date manipulation. With the temporal API, you can create dates without a time zone, specify dates without a year, and create durations without being attached to a specific date. The API also provides features for finding the difference between two dates. Invokers is a declarative click handlers API that eliminates the need for JavaScript. Speculation API enables pre-rendering and pre-loading of pages, improving performance. The CSS Anchor API allows positioning elements based on another element's location. Web components are encapsulated, framework-agnostic, and easy to use, offering a standardized approach for building reusable UI components. Building media UI components, like video players, is made easier with web components like Shoelace. Transformers JS allows running AI models in JavaScript for tasks like emotion detection and background removal. Python doesn't run in the browser, but JavaScript does. Small AI models can be loaded and executed faster in the browser using technologies like WebGPU. Animate height auto transition using calc size. Apply starting styles to elements for smooth animations. Use Vue transition for CSS and JavaScript animations. Syntax website with Vue transition for smooth page transitions. CSS relative colors allow for lighter or darker shades. Scope CSS ensures styles only apply to specified div containers. Web primitives facilitate modern JavaScript code. You can create web requests and receive web responses using the same primitives on both the client and server. There are many new web standards that work everywhere and frameworks like Hano and Nitro are built upon them. The select and Popover elements are accessible by default. Most of the discussed features will be available in all browsers by 2025. The future of web development with AI is uncertain, but web developers should embrace AI tools to improve efficiency. Implicit CSS lazy loading depends on whether it's prefetching or pre-rendering. Wes Boss discusses the specific features he is excited about in web development, including starting style, calc auto, and allowed discrete. He shares his preferred way of staying informed on new web development discoveries, emphasizing the importance of being part of the community and keeping up with industry discussions. Wes also mentions reading W3C meeting notes and recommends following the Twitter account Intent2Ship to stay updated on upcoming CSS features. Lastly, he discusses the potential impact of the new Scope CSS feature on developers' management of styles.

Is React really dying? React is dead. Let's take a look at the numbers. Svelte is getting 1.5 million downloads per week. Angular is pulling 3.5. Probably not a competitor with React. React dwarfs everything with 25 million downloads a week. React is incredibly popular with 4 million users and developers. Despite some criticism, a survey shows that 71% of respondents liked React, while only 28% didn't. React's flexibility and options can be overwhelming for beginners. React's complexity has increased, causing confusion for beginners. Memory management, overcomplicated architecture, and innovation fatigue are common challenges in React. React 19 is delayed due to suspense issues. React server components are a favorite innovation. Qwik's hydration model is cool. Qwik is amazing, and it would be cool to see something like it for React. AI can help you get 80% there, but you still need an actual developer to tweak and clean up the code. Tab AI keeps your workflow going. React's popularity is undeniable. The momentum behind React is strong, and it's unlikely to fade away anytime soon.

We surveyed thousands of developers to show that a louder audience leads to a better presentation. There has been a shift in web app development towards server-first architectures, which has improved full-stack capabilities but at the cost of complexity and divergence from the client-centric approach. Tanstec Start is a meta-framework that aims to provide the best client-side authoring experience with powerful server-side primitives. The Tansec Router supports advanced routing features, URL state management, and JSON storage. Combined with the server-side rendering capabilities of TanStack Start, it becomes even more powerful. The TanStack Router has isomorphic loaders and integrates seamlessly with TanStack Query for additional features like polling and offline support. UseSuspenseQuery allows for dynamic streaming of data during SSR. TanStack Start also offers server-side features, API routes, server functions, and middleware. The future plans include RSCs, websockets, real-time primitives, and static pre-rendering. TanStack Start is now in beta and is suitable for building React apps. It is open source.

In this talk, the speaker aims to build an accurate understanding of how the new React compiler works, focusing on minimizing re-renders and improving performance. They discuss the concept of memoization and how it can be used to optimize React applications by storing the results of function calls. The React compiler automates this process by analyzing code, checking dependencies, and transpiling JSX. The speaker emphasizes the importance of being aware of memory concerns when using memoization and explains how the React compiler detects changes in function closure values. They also mention the Fibre Tree, which drives the reconciliation process and helps optimize performance in React. Additionally, the speaker touches on JSX transpilation, compiler caching, and the generation of code. They encourage developers to understand the code generated by the compiler to optimize specific sections as needed.

My goal with this talk was to answer the question of why we have another test runner. The talk breaks down the history of web testing into three chunks: the click-through era, browser war one, and browser war two. It discusses the motivations behind browser test runners and node test runners, highlighting Karma as the first node-based runner that gained popularity. The rise of node-based test runners like Ava, Tape, Mocha, and Jest is attributed to their stability and ease of use compared to Karma. Jest faced challenges with module loading and transpiling, but its non-opinionated abstraction made it a suitable choice. The shift towards environment-aware runners like VTest allows for safer testing and aligns with the need for transpilation across different environments. Lastly, the talk touches on the future of test tooling and the implications of AI on testing.

AI is transforming software engineering by using agents to help with coding. Agents can autonomously complete tasks and make decisions based on data. Collaborative AI and automation are opening new possibilities in code generation. Bolt is a powerful tool for troubleshooting, bug fixing, and authentication. Code generation tools like Copilot and Cursor provide support for selecting models and codebase awareness. Cline is a useful extension for website inspection and testing. Guidelines for coding with agents include defining requirements, choosing the right model, and frequent testing. Clear and concise instructions are crucial in AI-generated code. Experienced engineers are still necessary in understanding architecture and problem-solving. Energy consumption insights and sustainability are discussed in the Talk.