Sam tells Ryan about his experience setting up an in-browser code editor with CodeMirror that he plans on using for blog posts and code recipes, as well as what he thought about using Radix Themes for the first time in earnest on a side project of his currently styled with Tailwind. Topics include: 0:00 - Intro 4:01 - Building an authoring tool wit…

Sam and Ryan talk about why it’s better to think of throw as a general-purpose JavaScript language feature rather than something that should only be used for error handling. They discuss the ambiguity around the phrase “error handling”, situations that call for dealing with errors locally vs. globally, and how throw can be useful for non-error cont…

Sam and Ryan discuss the core values of the Next.js framework, and how those values motivate several of the framework’s design decisions. They talk about caching, why layouts don’t have access to the URL, and why the router doesn’t expose navigation events, as well as how developers should think about extending Next’s functionality with their own a…

Sam talks to Ryan about refactoring an MDX blog post to a React Server Component. They discuss how RSC’s ability to render server-side content with “client-side holes” turns out to replace MDX for many uses cases. They also talk about other tools that are (surprisingly) a conceptual subset of the RSC architecture, such as custom Webpack loaders. To…

Sam and Ryan read and discuss the latest update from React Labs. Topics include: 0:00 - Intro 5:26 - Opening 6:18 - React Compiler 27:27 - Actions 51:44 - Asset loading 1:13:06 - Next Major Version of React 1:15:42 - Activity Links: React Labs blog post Sam’s video on Strict ModeAv Frontend First

Sam and Ryan discuss the intuition behind React Transitions, and why React’s new useOptimistic hook is a good fit for building a URL-driven filter panel that stays fully responsive to client interactions. Topics include: 0:00 - Intro 1:12 - The problem: In a world of Server Components, URL updates are blocked by a server-side roundtrip 10:44 - Atte…

Ryan and Sam discuss the purpose and usage of the useOptimistic() hook, a new experimental API from React. Topics include: 0:00 - Intro 2:18 - Problem: RSCs require a server roundtrip before the UI can be updated 10:13 - Solution: useOptimistic() lets you merge ephemeral client-side state with server-side data so you can update the UI during a Serv…

Ryan and Sam discuss the purpose and usage of the cache() function, a new experimental API from React. Topics include: 0:00 - Intro 2:29 - Caching in Next.js vs. React cache() 8:11 - Why React invalidates the cache for each server request 14:43 - How cache() enables colocation of data-fetching code 16:14 - Using cache() to share CPU-heavy or I/O-bo…

Sam and Ryan talk about Advanced Radix UI, Build UI’s newest course. They also read and discuss a blog post that describes the RSC architecture in terms of two processes: React Server and React Client. Topics include: 0:00 - Intro 0:49 - Ceilingless libraries + Advanced Radix UI 21:02 - Read and discuss: “RSC is React Server + Component” Links: Adv…

Ian Landsman & Aaron Francis join Sam to discuss React Server Actions & Server Components, why it's important to have one set of opinions, and yes, the infamous SQL Injection Slide at NextConf. This is a crossover episode with the excellent podcast Mostly Technical. Topics include: 0:00 - The Most Memed Man on the Internet 09:06 - High Floor vs. Hi…

Sam and Ryan talk about the key parts of Remix’s architecture in the context of the Work Journal app from Build UI’s latest course. They discuss how Remix’s conventions around Links, Forms, Actions, and Loaders allow developers to eliminate boilerplate and take advantage of the best HTTP has to offer, while still providing a seamless way to enhance…

Ryan continues to share the details behind his custom RSC implementation. He talks with Sam about how Server Actions allow the client to reference server-side code (in the same way client components allow the server to reference client-side code), how Server Actions are bundled and invoked, and the security concerns associated with blurring the lin…

Ryan shares how building his own RSC implementation from scratch helped him better understand React’s new paradigm. He and Sam talk about how a client React app can fetch an RSC Payload from a server endpoint to update the UI, how an RSC server renders and bundles Client code that’s part of a Server Component tree, and how a client-side Router can …

Ryan and Sam talk about how to invalidate Next.js’ client-side cache when a different session makes changes to backend data, and ultimately discuss whether clicking a link to a URL vs. hitting refresh on that same URL should render the same page if no backend data has changed. Topics include: 0:00 - Intro 1:00 - Suspense boundary identity and the A…

Tim joins Sam to talk about his work on the new app router in Next.js 13. He explains how the app router leverages Server Components and React’s new cache API to bring a new level of composability to server-side code, how Server Actions are being designed to enable partial revalidation in a single round trip to the server, and how to think about UI…

Sam and Ryan discuss how TypeScript helped them understand the mechanics of how props get passed from Server Components to Client Components, and how to properly type client component props if the prop starts out as a rich data type on the server. They also clarify some points from last episode’s discussion about the RSC payload. Topics include: 0:…

Sam and Ryan explore different ways to think about the RSC architecture, including what problems RSC solve, why RSC are valuable even in a world without server-side rendering, and how React’s reconciliation phase enables RSC to make partial updates to the UI as a result of server-side events. Topics include: 0:00 - Intro 5:45 - What if RSC were int…

Ryan shares his thoughts on how Server Actions and the useFormStatus hook are letting him build reusable pending UI for any form in his Next.js side project. Sam talks about how TypeScript prevents an entire class of data-loading bugs that have plagued single-page applications built with a client-side cache. Topics include: 0:00 - Tailwind Connect …

Sam and Ryan share their thoughts on the recent React Roundtable with core team members Sebastian Markbåge and Andrew Clark. They talk about the evolution of Server Components from the perspective of solving the problem of fetching data in React apps, how SPAs have a lower baseline but higher ceiling in terms of the user experience they can deliver…

Sam and Ryan use some recent Twitter discussion on copying + pasting code (instead of abstracting it for reuse) as a springboard for a discussion about how their thinking on low-level UI components and design systems has changed over the years. Topics include: 0:00 - Intro 2:16 - Copy-paste vs. creating abstractions 11:43 - How we used to build sha…

Sam and Ryan share their learnings from working with Server Components in earnest over the past week. They talk about how Server Components can simplify client components by passing them props, why it makes sense for a component that can run everywhere to be a Server Component by default, whether RSC is causing unnecessary churn in the ecosystem, a…

Sam shares some recent learnings around hydration mismatches when rendering time zoned dates on the server and the client. He talks about using the TZ environment variable to reproduce the issue locally, and how he solved his problem by avoiding impure format and transformation functions from date-fns. Topics include: 0:00 - Intro 0:50 - Sever vs. …

Sam and Ryan talk about using MJML to design, build and send transactional emails with React directly in the browser. They also chat about how to use Framer Motion to get a CSS radial gradient to follow the mouse cursor and the differences between React state, refs, Motion Values, and external stores. Topics include: 0:00 - Intro 1:10 - Building in…

Sam and Ryan talk about building an animated tabs component with CSS’s mix-blend-mode property and Framer Motion’s layout animations. They also talk about how to use the URL constructor in JavaScript to help implement secure arbitrary redirects, as well as their initial reactions to new framework APIs that blur the lines between server and client c…

Sam tells Ryan about his experience building an animated toggle with React Aria Components. He gives his first impressions of the new library and discusses some of functionality included from the lower-level React Aria hooks. Ryan also talks about his recent use of GitHub Copilot. Topics include: 0:00 - Intro 1:15 - Using GitHub Copilot to keep you…

Sam and Ryan talk about updating Build UI to support lifetime memberships. They chat about the site’s current architecture, the strengths and weaknesses of objects vs. functions, how the full stack JavaScript community could benefit from a proper model layer like ActiveRecord, the challenges of using GraphQL on the backend, Prisma, and more. Topics…

Ryan and Sam use some recent Twitter conversation to guide a discussion about the design and purpose of React Server Components. They talk about how client trees and rendered on the server today, why a server-side rendered prepass is wasteful in light of RSC, how hydration of a client tree works, why RSC are never hydrated, how RSC is a purely addi…

Sam and Ryan share their thoughts on the latest server-centric developments taking place among React frameworks like Remix and Next.js. They discuss the declarative nature of HTML and HTTP, the evolution of frontend development from imperative libraries like jQuery to declarative libraries like React, why developers started creating SPAs in the fir…

Sam and Ryan have an open-ended conversation about different caching APIs and what kinds of benefits they might afford app developers. They discuss transparent caching layers, cache keys and surrogate keys in systems like Fastly, how SSG is effectively a high-level caching solution, Next.js 13.2’s cache API, Russian doll caching in Rails, whether a…

Sam and Ryan chat about their recent work migrating Build UI from a statically generated site to a run-time server-rendered app using Next.js. They talk about their past experience working on server-rendered apps, the problems that static sites were created to solve, and the tradeoffs involved within the static-to-dynamic continuum. Topics include:…

Ryan talks about a demo he built in Next.js 13 with React Server Components. He explains how RSC driven by the URL eliminated client-side states, how he used React 18 Transitions to enhance the UI, and how he was able to fine-tune the experience differently for the initial render vs. subsequent client-side navigations. Topics include: 0:00 - Intro …

Ryan and Sam read a recent article by Derrick Reimer called “Ship Small, Ship Fast” and offer their thoughts on it. They discuss how implementation details can lead to reductions in scope, the relationship between shipping small and agile, and why quickly getting the first steps of a user flow into production is a good protocol for software teams t…

Sam and Ryan talk about seams in TypeScript programs where lies can sneak in. They chat about how API calls, form inputs, and URLs all relate to this problem, the similarity between drifting types and service mocks in testing, zod, and how type-safe languages like Elm eliminate this problem entirely. Topics include: 0:00 - Intro 2:41 - Lying in Typ…

Ryan tells Sam about a side project of his that involves running the text-to-image deep learning model Stable Diffusion on his laptop in response to web requests. Ryan asks Sam questions about animating this UI, including how to animate indeterminate progress, how to avoid unintentional layout animation, and how to automatically repeat a set of ite…

Ryan talks about the pros and cons of exposing Build UI’s environment-independent CMS from Hasura via schema stitching. He also talks about writing a Postgres function to add a derived field to a database model. Sam shares a debugging story about fixing his personal website due to a breaking change in a minor version of npm. Topics include: 0:00 - …

Sam and Ryan chat about how to avoid a flicker of content on initial render due to mismatched server/client rendering. They also chat about the pros and cons of React Hooks, and using StackBlitz containers to debug OSS issues. Topics include: 0:00 – Intro 1:46 – Ryan Florence’s tweets about Hooks, useEffect and refs 18:12 – How to avoid SSR/CSR ren…

Sam and Ryan chat about issues they’ve run into in the past when building media sites that store content alongside other dynamic data like user accounts, and how they’re using a CMS to alleviate these problems in Build UI. They also talk about the approach they’ll be using for access control to the CMS. Topics include: 0:00 – Intro 0:27 – Unintenti…

Sam and Ryan chat about building their new site using services, and how they’re thinking about testing it. They talk about how testability is one of the biggest costs of using third-party hosted services, why they continue to like services in spite of this downside, and the fact that you always end up testing your app whether you eventually automat…

Ryan shares his experience getting end-to-end type safety from a Hasura backend into a React application. He tells Sam about the different ways GraphQL codegen can be used to generate types, and how he ultimately landed on a solution that combines the TypedDocumentNode type and the zod library. Topics include: 0:00 - Intro 2:51 - Using GraphQL Lang…

Ryan tells Sam about some experiments he’s been running using Server Components in Vercel’s new edge runtime. He talks about how components that suspend in the node runtime cause the static build of your Next.js app to wait until they unsuspend, while components that suspend in the edge runtime stream back fallback responses as data is being fetche…

Sam and Ryan chat about issues with default HTML buttons on the web across different devices and browsers. They talk about the Extensible Web Manifesto, how the React Aria library helps standardize button behavior across platforms, and the difference between state-based and event-based animations. Topics include: 0:00 - Intro 2:09 – The problem wit…

Sam and Ryan talk about whether you should use merge commits or you should rebase commits in your PRs when working on large, fast-moving codebases. They also talk about implementing build-time client-side search with Stork, and why layering in animation code shouldn’t materially affect your existing React code. Topics include: 0:00 - Intro 1:48 – H…

Sam and Ryan read and discuss the first two sections of the new Next.js Layouts RFC, Nested Layouts and Server Components. They also reflect on their experience using nested layouts in other frameworks. Topics include: 0:00 – Intro - 10:21 – Layouts and creating UI (Apple Music example) - 33:40 – React Server Components - Links: Layouts RFC Framer …

Sam and Ryan talk about the new useEvent RFC, and how useEvent lets you extract event logic from your side effects. They also read and discuss Dan Abramov’s recent Twitter thread on how useEvent addresses the problems people are encountering with React 18’s Strict Mode behavior around running effects twice on mount. Topics include: 0:00 - Intro 0:3…

Sam and Ryan talk about the motivation behind the changes to Strict Mode in React 18, and in particular why React simulates an immediate unmount and remount by re-running component effects. They also talk about the tradeoff between database consistency and speed. Topics include: 0:00 - Intro 1:12 - The tradeoff between data that’s fast but stale, v…

Sam and Ryan share their experiences building with Remix for the very first time. Sam built a simple exercise tracking app using the Indie starter stack, and Ryan built a blog using server rendering in both Remix and Next.js, and talks about the differences between the two frameworks. They both discuss what the larger React community can learn from…

Sam and Ryan chat about Remix and the differences between data fetching and mutations on the client vs. the server. They also talk about whether a framework’s APIs or the actual apps it enables developers to build are more important when choosing which tool to use. Topics include: 0:00 - Intro 2:17 - What matters more to developers when choosing a …

Sam and Ryan chat about adding authentication-based route guards to Next.js, tradeoffs between one-shot data loading vs. reactive pages in React apps, and instrumenting errors with Sentry. Topics include: 0:00 - Intro 8:07 - Auth-based route guards and synchronized spinners in Next.js 26:34 - Tradeoffs of loading once on render vs. fully reactive p…

Sam and Ryan talk about why Suspense for Data Fetching isn’t ready yet, and how both it and the Server Components feature of React 18 rely on the ability to evict a cache that’s internal to React. They also talk about Transitions. Topics include: 0:00 - Intro 5:19 - Using startTransition with a router 9:36 - How React 18 yields 21:37 - Why both Sus…

Sam and Ryan chat about the differences between building internal apps vs. public websites, and why public sites get talked about more on forums like Twitter. They also talk more about their experiments with Suspense and Transitions in React 18. Topics include: 0:00 - Intro 2:35 - How to trigger Suspense by accessing an unresolved promise 11:04 - T…