Ryan talks to Sam about reproducing iOS's new image background treatment for his Open Graph Preview tool, opengraph.ing. They talk about different approaches for generating gradients from images, including finding the vibrant color of an image, luminosity-weighted averages, k-means clustering, and more.

Creating a background gradient from an image

Sam and Ryan talk about React 19's useActionState hook. They discuss how adding async functions to a plain React app introduces lots of in-between states that developers must grapple with, and how useActionState allows React to collapse and eliminate these states, bringing the simplicity of React's sync mental model to our async code.

Exploring useActionState

Sam and Ryan talk about using Cloudflare Tunnel for local development, the new React Compiler beta release, and why reading or writing refs during render violates the rules of React.

Cloudflare Tunnel | React Compiler | refs during render

Sam and Ryan talk about building a useAnimatedText hook that can animate streaming text. They also discuss how React code that uses state changes to approximate events can be simplified, and the benefits of having escape hatches when building UI with Catalyst.

useAnimatedText | Events vs. State Changes | Catalyst

Sam and Ryan talk about how frameworks and infrastructure evolve with each other, using Next.js as a representative example. They discuss how hosting providers like Heroku have always imposed certain constraints on apps, what features those constraints enable hosting providers to support, how burdensome those constraints are across different frameworks, and how frameworks that add infra-specific APIs can best communicate the costs of those APIs and the benefits they enable.

Can you self-host Next.js?

Tom Occhino, Chief Product Officer at Vercel and former Engineering Director at Facebook, joins Sam to talk about the pivotal moments in React's history. He talks about how React popularized the ideas of declarative rendering and unidirectional data flow, how GraphQL furthered React's goal of co-locating all the concerns of a particular piece of UI, the problems that GraphQL led to at Facebook and how Relay solved them, and how Suspense, Server Components, and PPR are the generalized spiritual successors to the stack used at Facebook.

Tom Occhino on the future of React

Sam and Ryan talk about render props in React. They discuss where they came from, how Hooks superseded them for sharing stateful logic, how data attributes compare to them for customizing styling, and how for certain complex components like forms they're still a great solution for accessing slices of internal state.

Render props

Sam and Ryan discuss controlled and uncontrolled components in React. They talk about how uncontrolled components can be thought of as components that manage their own internal state, why you should model your complex React components after the simpler APIs of native HTML elements like inputs, why you shouldn't try to make components that are both controlled and uncontrolled, and why making a new component boundary is sometimes all you need to make your custom components behave more predictably.

Controlled and uncontrolled components

Sam and Ryan talk about the pattern of building unstyled components with React. They discuss why unstyled components were created, how they improve upon composition patterns from UI libraries like Bootstrap, how they can be used to share behavior and logic without prescribing any styling opinions, and how they fit into a larger collection of React patterns that can be used to build more powerful components that avoid premature abstractions.

Unstyled React components

Sam and Ryan talk about what sorts of capabilities a tool should have to be considered a web framework. They discuss how frameworks tackle the complexity of getting different systems to communicate with each other, how good frameworks embrace the strengths and patterns of the language they're written in, and why frameworks and services are not in opposition to each other.

What is a framework?

Sam joins Lane Wagner in a crossover episode with the Backend Banter podcast. They talk about abstractions in frontend and backend frameworks, what JavaScript is doing differently from other languages and frameworks, why the frontend should drive the backend even if you're building in a server-side framework, and what's so special about React Server Components.

Crossover: Declaring War Against the Frontend

Sam and Ryan read and discuss a fantastic interactive blog post about queueing in HTTP written by Sam Rose.

Blog Post Club: Queueing - An interactive study of queueing strategies

Sam and Ryan discuss the new features in React 19 that will specifically benefit developers building single-page applications. They talk about how Suspense and Transitions let developers "teach" React about when their apps are in a loading or a pending state, how Client Actions improve upon using events in React 18 to handle data mutations, and how Actions enable React Components to automatically render and discard optimistic updates without any knowledge of the application's data layer. They also discuss several new Hooks like useOptimistic, useFormStatus, useActionState, and useOptimistic.

SPAs in React 19

Sam tells Ryan about a recent talk he gave at BigSkyDevCon. They chat about how backend frameworks are raising the ceiling of what UIs they’re capable of delivering, how frontend frameworks are raising the floor of what backend features they come bundled with, and what each community can learn from the other.

High floor, high ceiling

Sam and Ryan talk about the difference between the costs of building a feature and the benefits that feature brings to our end users. They discuss how libraries and frameworks can lower the technical cost of building a given feature, how Ryan Florence framed this calculation in his talk at Big Sky Dev Con, and how sometimes developers’ opinions and tastes about tech can smuggle their way from the cost side of the equation into the benefit side.

Technical Cost vs. Product Benefit

Ryan tells Sam about his experiments with using the new View Transitions API in a React photo gallery app. He talks about how he likes the flexibility of the API, how to think about integrating it into any client-rendered app regardless of the framework, and how he used a Promise with an Effect to tie a View Transition to a React Transition.

View Transitions in React

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.

CodeMirror | Radix Themes

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 control flow. They also discuss the problems with trying to shoehorn dynamic features into a static site.

Throw is about control flow – not error handling

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 application code.

The Philosophy of Next.js

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.

Beyond Data Fetching with RSCs

Sam and Ryan read and discuss the latest update from React Labs.

Blog Post Club: React Labs – What We’ve Been Working On

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.

Frontend First