React Advanced: React 19 Platform & Rendering Architecture

Overview

The reference for React-19-era platform capabilities and rendering architecture. This skill covers the features that reshape how modern React applications are built and optimized: the React Compiler and the end of reflexive manual memoization, concurrent rendering primitives, the use() hook, Actions and the form hooks, the React 19 ergonomic changes (ref as a plain prop, <Context> as provider, native metadata), advanced component-architecture patterns, rendering-performance engineering, and a conceptual treatment of the React Server Component boundary.

This guidance treats React 19 (Dec 2024) and React Compiler 1.0 (stable Oct 2025) as current. Pre-19 memoization advice — wrapping values in useMemo/useCallback/React.memo by reflex — is now an anti-pattern for new code. The compiler memoizes automatically. Authoritative documentation lives at react.dev; this skill distills and applies it rather than restating it.

Boundary Map: What This Skill Does NOT Cover

This skill stays focused on the React-19 platform and rendering architecture. Defer to the owning skill for everything else: