Today's Talk introduces the React compiler and its optimizations in React 19. The compiler handles optimizations internally, allowing existing optimizations to coexist. React 19 also brings server components, enhanced hooks, improved reference handling, and asset loading optimization. The React compiler follows the same principles as a typical compiler, with a Babel plugin and ESLint plugin identifying optimizations. The compiler optimizes components by performing in-place updates and reducing unnecessary re-rendering. The React compiler playground helps understand the optimization process. Caching JSX and configuring the React compiler can further optimize specific components. The React compiler is compatible with React 18 and 17 with some configuration, but using React 19 is recommended. Connect with the speaker for more information and subscribe to their YouTube channel. Thank you for watching!

Today's Talk is about Plux, a TypeScript application built with React and Three.js. The speaker discusses the challenges they faced with state management and their journey of switching libraries multiple times. They started with Redux but later introduced GSDAN, a faster and easier-to-maintain state management library. They optimized performance using selectors but realized it became a problem when dealing with documents with many nodes. They replaced Zustand with Jotite for better performance but encountered limitations and ultimately implemented a custom store, resulting in a significant improvement. The speaker emphasizes the importance of not locking into a solution and shares their timeline for the changes. They also mention considerations for state management, recognizing performance issues, and the possibility of open-sourcing their solution.

Hello everyone, and I'm so happy to see you here in React Day Berlin. This talk is on security and testing, two topics I'm passionate about. It's a wonderful allegory on web security using Plants vs. Zombies as inspiration. There are reasons to focus on testing as a line of defense. Learn your application and its vulnerabilities. Tests are the messenger, listen to them. Use OWASP's top 10 ranking to understand the most important security risks, including broken access control and cryptographic failure. Injection is a major security risk. Writing proper tests and using test cases can help mitigate this issue. To test for injection vulnerabilities, write negative tests that simulate extra injections in input fields. Test content security policies using Cypress. Implementing best practices and multiple defenses can keep attackers at bay. Automation is essential for detecting security issues in your app. Write test cases, use the features of test frameworks, and consider using different types of testing.

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 introduces web workers and discusses how they can handle large processing on the client side. Examples, benchmarks, and tradeoffs are provided. The benefits of using web workers are discussed, and a demo project using VanillaJS and the live server extension of VS Code is showcased. The speaker demonstrates how to use web workers to prevent the main thread from getting blocked during large operations. The process of creating a web worker file and moving functions to it is explained. The speaker also shows how to handle messages and perform operations with web workers. The final remarks include contact information and an invitation to check out the speaker's YouTube channel for React courses and articles.

Hi everyone! I'm Rohit, a founding engineer at Tria. We are working on bringing the world to Web3 using names. My talk is about gaining performance and taking runtime to build time. There is an upward trend in libraries towards build time optimization, especially in React. Build time optimization improves performance, reduces bundle size, and provides more predictable software. Babel is a free and open source JavaScript transpiler that allows leveraging latest JavaScript features and moving computationally heavy logic from runtime to build time. Building a Babel plugin involves checking for a style prop inside an HTML tag and searching for aliases or token values. The visitor pattern is used to define the JSX type of node and access its path and attributes. The plugin can be customized for different utilities by defining aliases and tokens in a config file. Helpful resources for understanding and building custom Babel plugins include the Babel handbook, Babel docs, astexplorer.net, and the speaker's Twitter account.

I'll speak today about the Temporal proposal, which adds modern date and time handling to JavaScript. Temporal is an API that'll be available in browsers soon and will add a built-in library for dates and times, avoiding the need for external libraries like Moment. It offers strong typing with different types for different data, such as calendar dates with or without time. Temporal objects are immutable and designed to work with JavaScript's internationalization facilities. It addresses deficiencies in the global Date object and introduces types like instant and plain types for accurate representation of time and dates across time zones. With the old Date, representing a date without a time can be problematic, especially in time zones where midnight is skipped due to daylight saving time. Temporal introduces types like PlainDate, PlainTime, PlainYearMonth, PlainMonthDay, and ZonedDateTime to accurately represent different scenarios. Additionally, there is a type called Duration for arithmetic operations and unit conversion. Now that I've introduced you to the cast of characters in Temporal, it's time to show how to accomplish a programming task. We'll start with an easy task: getting the current time as a timestamp in milliseconds using the instant type. To convert between Temporal types, you can either drop or add information. The toZonedDateTime method is used for conversion and requires adding a time zone and a time. Although Temporal objects are immutable, you can create new objects with replaced components using the with method. Migrating from the old Date object to Temporal offers a more reliable solution and avoids potential bugs. Check out the documentation for more details and enjoy using Temporal in your codebase!

Hello, everyone. My name is Tero Piirainen, a software engineer from Helsinki, Finland. I'm introducing a new UX framework for the web called Nue. It provides better tooling, code basis, and resulting websites compared to established frameworks like Next.js or Beat or Astro. Nue is incredibly fast, 100 times faster than Next.js, with improved hot reloading times. Simplicity is a key advantage of Nue, offering instant browser reactions to saved files and quick updates with hot reloading. Nue emphasizes timeless skills and focuses on design engineering, transitioning from JavaScript to modern CSS. Gnu, a component of Nue, focuses on CSS and offers small and fast websites with built-in turbo-linking and view transition motion effects. Overall, Nue and Gnu provide a simpler, faster, and more flexible development experience with a focus on user experience and design engineering.

Thank you for joining my session on untangling your dependencies. I encountered errors when trying to update dependencies in the project, leading to a tangled mess of issues. Managing dependencies can be like working with a ball of yarn, trying to knit a project. I'll share my favorite practices for managing dependencies and provide some background about myself. Leonardo da Vinci said, 'art is never finished, only abandoned,' and this applies to software as well. I'll share tricks and tips for managing complex dependency management systems and understanding different types of dependencies. Working with dependencies often comes with challenges, especially when using React Native. Examples of tools that assist with managing dependencies include yarn upgrade interactive, NPM check updates, and React Native upgrade helper. When encountering issues, breaking them down into smaller chunks helps find solutions. To tackle dependency issues, focus on one platform at a time and choose the right tools. Tools like NPM why and Clip can help identify unnecessary dependencies and unused files. Monorepos and tools like Yarn workspaces and npm shrinkwrap are useful for managing monorepos. Bleeding edge branches and dependency updates allow for incremental and broken commits. Regular updates are recommended to stay aligned with platform changes.