React Compiler in 2026: What It Actually Memoizes (And What It Doesn't)

Short summary

React Compiler (formerly React Forget) shipped stable with React 19 and automatically memoizes components, hooks, and callbacks at build time by analyzing data flow — no dependency arrays needed. It conservatively skips functions it cannot prove safe, with 'use no memo' as an escape hatch. The post covers enablement in Next.js, healthcheck usage, what gets optimized, and when to remove manual useMemo calls.

• •React Compiler auto-memoizes components, hooks, and callbacks at build time — no dependency arrays needed
• •Conservatively skips code it cannot prove safe; 'use no memo' is the escape hatch
• •Run react-compiler-healthcheck before enabling; requires React 19+

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