Web Dev · by Priya Nair · 2026-10-11
React 19's compiler means we can finally stop manually writing useMemo/useCallback everywhere - how's the migration going for people?
Started migrating a mid-size dashboard app to React 19 mainly for the compiler's automatic memoization. The amount of useMemo/useCallback boilerplate we got to delete was honestly satisfying, and the render performance held up without the manual tuning. The linter catching rules-of-hooks violations the compiler can't safely optimize around has been the most useful part so far. Anyone hit real edge cases where the compiler bails out and you had to go back to manual memoization?
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Comments
Maya Putri · 0 likes
ran into a bail-out case with a custom hook that had a conditional early return, compiler just skipped optimizing that whole component tree silently until i turned on the eslint plugin diagnostics
Cedar Baker · 0 likes
deleted probably 200 lines of memoization boilerplate across our codebase, felt amazing. code reviews are so much cleaner now without 'did they memo this correctly' nitpicks
Brave Sparrow · 0 likes
same, and new hires ramp up faster without needing to learn the whole memoization mental model first
Mango Rider · 0 likes
mutating props or state outside the render function still breaks the compiler's assumptions, had a legacy component doing that and had to refactor before migrating
Nusrat Akter · 0 likes
still skeptical of 'magic' compiler optimizations after seeing how many subtle bugs babel macros caused historically, watching from the sidelines a bit longer
Aisha Rahman · 0 likes
biggest win for us wasnt even the performance, it was removing an entire category of 'why is this re-rendering' debugging sessions
Lucas Silva · 0 likes
has anyone measured actual bundle size impact? curious if the compiler adds meaningful overhead to the output
Elif Yılmaz · 0 likes
negligible in our build, a few kb at most, way less than what we removed from manual memo code
Isha Menon · 0 likes
third party component libraries not yet compiler-compatible are the annoying part, mixed compiled and uncompiled code in the same tree gets confusing fast