Tech talks & workshops by core teams and top engineers

React Query is a popular library for managing asynchronous state—most often state returned from data fetching. Its popularity has grown significantly over the past few years, with nearly 20% of all React applications now using it.
In this talk, maintainer Dominik will explore the other side—...

Today's Talk focused on performance optimization in React apps, specifically in handling and rendering enormous amounts of data. The speaker discussed various techniques and tools to achieve better performance, such as optimizing data relay, rendering, data processing, memory usage, and denormalization. They also highlighted the importance of optimizing network performance, payload size, and request handling. The Talk emphasized the need to measure before optimizing, focus on bottlenecks, and make small improvements that actually benefit users. Overall, the Talk provided valuable insights and recommendations for improving performance in React apps.

Hey, I'm Sid, and I work on the design systems team at GitHub. Let's talk about building accessible React components with a focus on screen readers. Use the correct HTML element for accessibility. For example, on GitHub, there are three tabs with options. These tabs are made using buttons. Let's see how a visually impaired person using a screen reader would access this website. What do they see? I'm going to enable the screen reader and walk you through what happens. When turning on the screen reader, it sets the context and tells you where you are. For example, on the React app, a button labeled 'Code' has focus and a menu popup. Inside the popup, there are several buttons with different labels. Something interesting happens. If I can't see the UI, I'm hearing buttons but no tabs. Screen readers cannot infer things like tabs from visual design. To provide this information, we can use the ARIA spec and its roles. By adding a role tab list to the div and role tab to each button, the semantics are conveyed. The role overrides HTML semantics. Screen reader identifies tabs, pronounces 'code spaces'. Default behavior of a tab is auto-focus. We can add aria-selected attribute to specify selection. Using React, I'm using an expression to set aria-selected based on the selected tab. The navigation into the tab panel is disorienting. There are separate groups for the tab list and tab panel, and there is a need for navigation between them. Use arrow keys to navigate within the widget. Remove tabs from the tab index, only the selected tab should be focusable. Implement arrow keys for navigation. Press tab to enter the tab panel. Press shift tab to go back up. Keyboard navigation is a common pattern extracted into a hook. Decide which keys to bind based on the widget type. Change selected tab on focus. Consider the ARIA authoring practices guide for keyboard interactions. Differentiate between instant and activated tabs. Follow the ARIA spec and use the APG as an informative resource. Screen readers may not always follow the ARIA authoring practices guide. Use correct HTML elements, add ARIA roles, properties, and states. Implement keyboard navigation. Use a GitHub example of notification settings with proper semantic elements. When selecting notification channels, the options are presented in a pop-up. The focus is on the first checkbox, indicating that it is the first option. The screen reader reads the status of each option. After selecting the desired option, the form can be submitted. The change is saved and the user is notified. The focus is recontextualized on the collapsed menu popup button. Not rendering the fourth option in certain conditions hides it from screen users. Removing the conditional and disabling the fourth checkbox until necessary eliminates this issue. Using IR disabled instead of disabled makes the element accessible for screen reader and keyboard users without affecting styling or click cancellation. You have to add your own class name and make sure it is disabled. It is accessible by keyboards. Voiceover on Mac uses 'dimmed' to signify IR disabled. Adding another span that requires at least one channel. Additional descriptions can be added using aria-describeby. SCREEN READER Only notify for failed workflows. Requires at least one channel to be selected. Dimmed unticked. Tick box. Now you know the label, why it is disabled, and that it's dimmed. And let's see if it's If I mean. Never. Menu popup collapsed. This flow seems more intuitive. You know all your options up ahead. One option was disabled, enabled something else, and it became enabled again. Much more clear. Feels like a better UI. We need to design with accessibility in mind. Accessibility isn't something that you can just sprinkle on in the end. We have to bring it way earlier in the stage. Be careful when disabling elements. Use RLDisabled. Short list of six things to consider. Links on my website. Follow me on Blue Sky.

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.

The Talk discusses the use of the Use hook in React and its ability to be used conditionally. It explains the concept of the fiber tree and how hooks values are stored in memory. The Talk also delves into the conditional use of useContext and how it differs from useState. It explores the process of updating context values and optimizing context rendering. The role of the provider in managing context values and rendering is emphasized.

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.

Hello everyone! I'm Anthony Fu, a coaching member of Vit, Vue, and Nuxt. Today, I'll share my findings and practices in exploring ESLink and its ecosystem. ESLink v9.0 released 7 months ago with the new FlatConfig, which simplifies plugin configuration and provides full control and customization in JavaScript. Migrate legacy config to FlatConfig with eslink-migrate-config CLI and use eslink-config-inspector for visualized step tool. Flag config utilities make config customization easier and allow project-aware configs. ESLink is a powerful AST toolkit and can be used as a formatter. Use ESLink for maintaining stylistic rules and customize it to fit your project's needs.

Mark Erickson explains the history, creation, evolution, and benefits of Redux. Redux was designed to make state updates and action history maintenance easy, incorporating functional programming principles. Redux Toolkit was created to simplify Redux usage. Redux is still a valid choice for its consistent pattern and separation of state from UI. The decision to use Redux depends on the specific use case and the need for centralized state management.