react-development

Replace forwardRef with ref as a regular prop, render Context directly instead of Context.Provider, swap ReactDOM.render for createRoot from react-dom/client, and replace propTypes/defaultProps with TypeScript interfaces and ES6 default parameters.

Tailwind v4 moves all configuration into CSS using the @theme directive after @import "tailwindcss". Define colors, fonts, spacing, and breakpoints as CSS custom properties like --color-primary, which automatically generate corresponding utility classes.

useActionState replaced useFormState for managing form submission state including pending status, errors, and results. It takes an async action function and initial state, returning the current state, a submit action, and an isPending flag.

Yes, but their meanings shifted down one size step. The old shadow-sm is now shadow-xs, and old shadow is now shadow-sm. The same renaming applies to blur, drop-shadow, rounded, and backdrop-blur utilities.

Default to Server Components for data fetching, database queries, and secret handling since they render outside the client bundle. Add the 'use client' directive only when you need hooks, event handlers, or browser APIs.

Tailwind v4 removed all *-opacity-* utilities like bg-opacity, text-opacity, and ring-opacity. Use the color opacity modifier syntax instead, such as bg-black/50 or bg-blue-500/50, which appends the opacity directly to the color utility.