Chapter 4 of 8 · 5 practices · 3 min · 4-question quiz
Performance and memoization
How to keep React fast in 2026: let React Compiler memoize, measure before you optimize, and keep urgent updates responsive.
Start: Turn on React Compiler instead of memoizing by hand5 practices in this chapter
- 1Turn on React Compiler instead of memoizing by handReact Compiler 1.0 has been stable since October 2025. It analyzes your components at build time and adds memoization automatically, which removes most of the need for manual
useMemo,useCallback… - 2Use useMemo and useCallback only as an escape hatchWith React Compiler on,
useMemoanduseCallbackbecome an escape hatch, not a habit. Removing existing memoization can change what the compiler outputs, which is why the React team advises… - 3Measure with the React Profiler before you optimizeGuessing where a slow screen spends its time usually leads to the wrong fix. Measure first. Open React DevTools and record a profile while you reproduce the slow interaction; Look at which components…
- 4Keep typing responsive with transitions and deferred valuesNot every update is equally urgent. Typing in a search box must feel instant; re-rendering a big results list can wait a moment.
- 5Load heavy, rarely used components lazilyA chart library, rich text editor or admin panel that only some users open should not be in the bundle every visitor downloads.
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