React

Component-based UI library for building interactive interfaces. React 19 brings server components, the use hook, a compiler that eliminates manual memoization, and form actions for progressive enhancement.

Overview

• What: UI library (not a full framework) - pair with Next.js, Remix, or Vite for routing/SSR
• Install: npm create vite@latest my-app -- --template react-ts (client) or npx create-next-app@latest (full-stack)
• Key concepts: Components, JSX, hooks, server components, actions
• React 19: use hook, React Compiler, server/client components, useActionState, useOptimistic

Contents

Concepts

• Component Model - Functions returning JSX, props, composition, server vs client components
• Hooks - Core hooks, the use hook (React 19), custom hooks, rules
• Server Components - RSC architecture, boundaries, bundle impact, framework support

Quickstart

• Setup - Vite + React + TypeScript + Tailwind from scratch
• First App - Build a task list with state, data fetching, and form actions

Deep Dives

• Data Fetching - use + Suspense, TanStack Query, server component patterns
• State Management - Local, shared, server, and complex state patterns
• React Compiler - Automatic memoization, setup, what you can stop writing
• Forms and Actions - Server actions, useActionState, optimistic updates

Notes

• Gotchas - React 19 breaking changes, boundary mistakes, profiling tips

Resources

• React docs
• React GitHub
• React 19 blog post
• React Compiler docs
• Next.js docs