React 19 ships the React Compiler as an opt-in production feature, performing automatic memoization at build time and making useMemo, useCallback, and React.memo largely unnecessary for most applications. The compiler statically analyzes component code, identifies reactive scopes, and inserts per-slot cache boundaries—often
Table of contents
Table of ContentsHow React Re-rendering Works Today (and Why It's a Problem)What Is the React Compiler?Automatic Memoization in PracticeSetting Up the React Compiler in Your ProjectWhat the Compiler Cannot Do (and When You Still Need Manual Optimization)Migration Strategy for Existing CodebasesReal-World Performance ImpactWhat This Means for the Future of React DevelopmentSort: