You have always been able to just calculate in render, but useMemo didn't exist, so for expensive calculation some of us used a memoized function. But yeah, most people probably didn't do that.
November 6, 2025 at 6:27 PM
You have always been able to just calculate in render, but useMemo didn't exist, so for expensive calculation some of us used a memoized function. But yeah, most people probably didn't do that.
Um que me fez quase chorar foi algo assim:
const x2 = useMemo(x => x, [x]);
const x2 = useMemo(x => x, [x]);
October 20, 2025 at 4:01 PM
Um que me fez quase chorar foi algo assim:
const x2 = useMemo(x => x, [x]);
const x2 = useMemo(x => x, [x]);
Just published an #ESLint plugin to catch cases of manual memoization (React.memo, useMemo, useCallback), reminding you to let #ReactCompiler work its magic ✨
Oh, and the docs include React Compiler Playground links so you can see the automatic memoization in action!
github.com/BellCubeDev/...
Oh, and the docs include React Compiler Playground links so you can see the automatic memoization in action!
github.com/BellCubeDev/...
GitHub - BellCubeDev/eslint-plugin-react-no-manual-memo: ESLint plugin for React Compiler users to flag any usage of useMemo, useCallback, and React.memo—both to catch instinctive memoization and to b...
ESLint plugin for React Compiler users to flag any usage of useMemo, useCallback, and React.memo—both to catch instinctive memoization and to bring memoization up in code reviews if manual memoizat...
github.com
October 5, 2025 at 7:47 PM
Just published an #ESLint plugin to catch cases of manual memoization (React.memo, useMemo, useCallback), reminding you to let #ReactCompiler work its magic ✨
Oh, and the docs include React Compiler Playground links so you can see the automatic memoization in action!
github.com/BellCubeDev/...
Oh, and the docs include React Compiler Playground links so you can see the automatic memoization in action!
github.com/BellCubeDev/...
今日のZennトレンド
React Compilerを有効にして9ヶ月が経ちました
記事では、React Compilerを約9ヶ月使用した経験を共有。
プロダクションで重大な不具合は起きていないが、refやreact-hook-form関連で意図しない挙動があり、対応が必要だった。
特にwatchやformStateはuseWatch/useFormStatusで解消。
next devとbuildで挙動が違うケースに注意が必要。
useMemoなどを書かなくて済むメリットはあるが、導入にはライブラリとの相性や検証コストの考慮を推奨している。
(204文字)
React Compilerを有効にして9ヶ月が経ちました
記事では、React Compilerを約9ヶ月使用した経験を共有。
プロダクションで重大な不具合は起きていないが、refやreact-hook-form関連で意図しない挙動があり、対応が必要だった。
特にwatchやformStateはuseWatch/useFormStatusで解消。
next devとbuildで挙動が違うケースに注意が必要。
useMemoなどを書かなくて済むメリットはあるが、導入にはライブラリとの相性や検証コストの考慮を推奨している。
(204文字)
React Compilerを有効にして9ヶ月が経ちました
はじめにReact Compilerを2024年7月末に導入し、2024年10月中旬からプロダクション利用を開始して現在(2025年5月中旬)に至りますこれまでに起きたことや感想を共有したいと思います 前提 技術スタックNext.jsのPages Routerを使用し、サーバー側で動く処理はほぼないreact-hook-formを使用reactStrictModeはtrue導入時にeslint-
zenn.dev
May 12, 2025 at 9:15 AM
今日のZennトレンド
React Compilerを有効にして9ヶ月が経ちました
記事では、React Compilerを約9ヶ月使用した経験を共有。
プロダクションで重大な不具合は起きていないが、refやreact-hook-form関連で意図しない挙動があり、対応が必要だった。
特にwatchやformStateはuseWatch/useFormStatusで解消。
next devとbuildで挙動が違うケースに注意が必要。
useMemoなどを書かなくて済むメリットはあるが、導入にはライブラリとの相性や検証コストの考慮を推奨している。
(204文字)
React Compilerを有効にして9ヶ月が経ちました
記事では、React Compilerを約9ヶ月使用した経験を共有。
プロダクションで重大な不具合は起きていないが、refやreact-hook-form関連で意図しない挙動があり、対応が必要だった。
特にwatchやformStateはuseWatch/useFormStatusで解消。
next devとbuildで挙動が違うケースに注意が必要。
useMemoなどを書かなくて済むメリットはあるが、導入にはライブラリとの相性や検証コストの考慮を推奨している。
(204文字)
You shouldn't obsess over memoizing everything in React
I see many developers use useMemo and useCallback for every variable and function
This is inefficient, time-consuming, and ultimately useless most of the time
@tkdodo.eu wrote a really nice article about this
I see many developers use useMemo and useCallback for every variable and function
This is inefficient, time-consuming, and ultimately useless most of the time
@tkdodo.eu wrote a really nice article about this
August 20, 2025 at 9:56 AM
You shouldn't obsess over memoizing everything in React
I see many developers use useMemo and useCallback for every variable and function
This is inefficient, time-consuming, and ultimately useless most of the time
@tkdodo.eu wrote a really nice article about this
I see many developers use useMemo and useCallback for every variable and function
This is inefficient, time-consuming, and ultimately useless most of the time
@tkdodo.eu wrote a really nice article about this
The other thing is that even if there was an advantage to precomputing the context dependencies to determine if render should even run - we could expose an api to the compiler to hoist the checks before render so it’s identical to the useMemo. But it really doesn’t seem worth it in our explorations.
August 28, 2025 at 1:24 AM
The other thing is that even if there was an advantage to precomputing the context dependencies to determine if render should even run - we could expose an api to the compiler to hoist the checks before render so it’s identical to the useMemo. But it really doesn’t seem worth it in our explorations.
@rexxars just run @sanity_io studio with @reactjs 19 and the new React Compiler and it did optimizations in over 1300 components.
We can probably also delete about 9k of `useCallback` and 5k of `useMemo` in the Sanity monorepo (if my grep counting is correct). And that's just
We can probably also delete about 9k of `useCallback` and 5k of `useMemo` in the Sanity monorepo (if my grep counting is correct). And that's just
November 7, 2024 at 2:53 PM
@rexxars just run @sanity_io studio with @reactjs 19 and the new React Compiler and it did optimizations in over 1300 components.
We can probably also delete about 9k of `useCallback` and 5k of `useMemo` in the Sanity monorepo (if my grep counting is correct). And that's just
We can probably also delete about 9k of `useCallback` and 5k of `useMemo` in the Sanity monorepo (if my grep counting is correct). And that's just
So next time you find yourself writing a useMemo or useCallback, ask yourself if it's really achieving anything
Highly recommend the read
tkdodo.eu/blog/the-us...
Highly recommend the read
tkdodo.eu/blog/the-us...
The Useless useCallback
Why most memoization is downright useless...
tkdodo.eu
August 20, 2025 at 9:56 AM
So next time you find yourself writing a useMemo or useCallback, ask yourself if it's really achieving anything
Highly recommend the read
tkdodo.eu/blog/the-us...
Highly recommend the read
tkdodo.eu/blog/the-us...
Meta Quest Store saw 12% faster loads & 2.5× faster interactions with #React Compiler. ESLint and React violations looks solid too
I'm skeptical, but definitely going to try it out. Auto-memoization without manual useMemo/useCallback sounds promising.
react.dev/blog/2025/10...
I'm skeptical, but definitely going to try it out. Auto-memoization without manual useMemo/useCallback sounds promising.
react.dev/blog/2025/10...
React Compiler v1.0 – React
The library for web and native user interfaces
react.dev
October 29, 2025 at 11:40 AM
Meta Quest Store saw 12% faster loads & 2.5× faster interactions with #React Compiler. ESLint and React violations looks solid too
I'm skeptical, but definitely going to try it out. Auto-memoization without manual useMemo/useCallback sounds promising.
react.dev/blog/2025/10...
I'm skeptical, but definitely going to try it out. Auto-memoization without manual useMemo/useCallback sounds promising.
react.dev/blog/2025/10...
Al trabajar con hooks avanzados en React, me he dado cuenta de lo esencial que es entender cómo funcionan los efectos secundarios. Siempre que utilizo `useEffect`, me aseguro de definir claramente las dependencias para evitar bucles infinitos. También, me encanta usar `useCallback` y `useMemo` para
January 15, 2025 at 12:25 PM
Al trabajar con hooks avanzados en React, me he dado cuenta de lo esencial que es entender cómo funcionan los efectos secundarios. Siempre que utilizo `useEffect`, me aseguro de definir claramente las dependencias para evitar bucles infinitos. También, me encanta usar `useCallback` y `useMemo` para
¡Hola, amigos! Hoy quiero compartir algunos consejos para usar hooks avanzados en React. Primero, siempre que puedan, utilicen `useReducer` en lugar de `useState` para manejar estados complejos; facilita la lógica. También, no olviden el `useMemo` y `useCallback` para optimizar el rendimiento,
February 6, 2025 at 12:00 PM
¡Hola, amigos! Hoy quiero compartir algunos consejos para usar hooks avanzados en React. Primero, siempre que puedan, utilicen `useReducer` en lugar de `useState` para manejar estados complejos; facilita la lógica. También, no olviden el `useMemo` y `useCallback` para optimizar el rendimiento,
now that React compiler exists they should add a hook that pretends to be useMemo because useMemo is not just useful for value memoization but also as a code organization tool
August 28, 2024 at 7:48 AM
now that React compiler exists they should add a hook that pretends to be useMemo because useMemo is not just useful for value memoization but also as a code organization tool
Follow-up thought: If immutable data structures were the default, would React even need a compiler?
useMemo mainly prevents re-renders by stabilizing prop references, but with immutability, that would be automatic.
@danabra.mov Am I missing something here?
useMemo mainly prevents re-renders by stabilizing prop references, but with immutability, that would be automatic.
@danabra.mov Am I missing something here?
November 16, 2024 at 3:24 PM
Follow-up thought: If immutable data structures were the default, would React even need a compiler?
useMemo mainly prevents re-renders by stabilizing prop references, but with immutability, that would be automatic.
@danabra.mov Am I missing something here?
useMemo mainly prevents re-renders by stabilizing prop references, but with immutability, that would be automatic.
@danabra.mov Am I missing something here?
not sure tbh. might be easier. the nested useMemo thing requires redoing the hook list which is one of the main data structures. might also end up costing in the common case
May 3, 2025 at 10:44 PM
not sure tbh. might be easier. the nested useMemo thing requires redoing the hook list which is one of the main data structures. might also end up costing in the common case
Reactで覚えておきたいHook。
useState
useEffect
useMemo
useCallback
useTransition
useDeferredValue
memo
useState
useEffect
useMemo
useCallback
useTransition
useDeferredValue
memo
March 26, 2024 at 2:24 PM
Reactで覚えておきたいHook。
useState
useEffect
useMemo
useCallback
useTransition
useDeferredValue
memo
useState
useEffect
useMemo
useCallback
useTransition
useDeferredValue
memo
React LabsがReact Compilerを開発中
useMemo, useCallback, memo APIsみたいに手動で制御するのが美しくないって意見
使うことなくなるのかな
react.dev/blog/2024/02...
useMemo, useCallback, memo APIsみたいに手動で制御するのが美しくないって意見
使うことなくなるのかな
react.dev/blog/2024/02...
February 24, 2024 at 12:40 PM
React LabsがReact Compilerを開発中
useMemo, useCallback, memo APIsみたいに手動で制御するのが美しくないって意見
使うことなくなるのかな
react.dev/blog/2024/02...
useMemo, useCallback, memo APIsみたいに手動で制御するのが美しくないって意見
使うことなくなるのかな
react.dev/blog/2024/02...
Which is why you might want to consider utilizing useMemo; however, like useEffect, you shouldn’t overuse it. While there is no real downside with having useMemo versus not having it, it will make your code a lot less readable. #buildinpublic #react
May 8, 2025 at 6:50 PM
Which is why you might want to consider utilizing useMemo; however, like useEffect, you shouldn’t overuse it. While there is no real downside with having useMemo versus not having it, it will make your code a lot less readable. #buildinpublic #react
I accidentally learned how to use React's `useMemo` hook properly the other day and I'm fucking FURIOUS about it.
July 21, 2025 at 3:59 PM
I accidentally learned how to use React's `useMemo` hook properly the other day and I'm fucking FURIOUS about it.
Ever run into perf issues in your React app and wonder what was going on?
@shrutikapoor08.bsky.social will share her insights as a React developer at Slack and walk everyone through how to optimize performance using useMemo and useCallback hooks 🪝
@shrutikapoor08.bsky.social will share her insights as a React developer at Slack and walk everyone through how to optimize performance using useMemo and useCallback hooks 🪝
CascadiaJS 2024 | Speakers | Shruti Kapoor
In this hands-on talk where we'll explore React's useMemo and useCallback hooks together. As a React Developer at Slack, I'm excited to share insights from my React development journey, including expe...
cascadiajs.com
May 2, 2024 at 10:28 PM
Ever run into perf issues in your React app and wonder what was going on?
@shrutikapoor08.bsky.social will share her insights as a React developer at Slack and walk everyone through how to optimize performance using useMemo and useCallback hooks 🪝
@shrutikapoor08.bsky.social will share her insights as a React developer at Slack and walk everyone through how to optimize performance using useMemo and useCallback hooks 🪝
You can make uSES work with hydration & suspense by using useDeferredValue+useMemo.
September 14, 2025 at 4:46 PM
You can make uSES work with hydration & suspense by using useDeferredValue+useMemo.
🤔 Let's say you need to initialize a resource in a component only once. If you do it without any additional adjustments, it will be initialized on every re-render. So, you might think useMemo is the answer for initializing it once. But that's not true, actually.
December 12, 2024 at 6:38 PM
🤔 Let's say you need to initialize a resource in a component only once. If you do it without any additional adjustments, it will be initialized on every re-render. So, you might think useMemo is the answer for initializing it once. But that's not true, actually.
<a href="https://zenn.dev/naon/articles/642370c620b217" class="hover:underline text-blue-600 dark:text-sky-400 no-card-link" target="_blank" rel="noopener" data-link="bsky">zenn.dev/naon/artic...
UseCallbackとuseMemoの違い
UseCallbackとuseMemoの違い
UseCallbackとuseMemoの違い
useCallbackとuseMemo useCalbackとは useCallbackは、再レンダー間で関数定義をキャッシュできるReactフック。 https://ja.react.dev/reference/react/useCallback…
zenn.dev
June 26, 2024 at 1:08 PM
<a href="https://zenn.dev/naon/articles/642370c620b217" class="hover:underline text-blue-600 dark:text-sky-400 no-card-link" target="_blank" rel="noopener" data-link="bsky">zenn.dev/naon/artic...
UseCallbackとuseMemoの違い
UseCallbackとuseMemoの違い
5/ 🔧 So, for optimization:
✅ Wrap components with React.memo.
✅ Cache values using useMemo.
✅ Optimize functions with useCallback.
✅ Use stable keys in lists. 🆗
✅ Wrap components with React.memo.
✅ Cache values using useMemo.
✅ Optimize functions with useCallback.
✅ Use stable keys in lists. 🆗
January 8, 2025 at 9:51 AM
5/ 🔧 So, for optimization:
✅ Wrap components with React.memo.
✅ Cache values using useMemo.
✅ Optimize functions with useCallback.
✅ Use stable keys in lists. 🆗
✅ Wrap components with React.memo.
✅ Cache values using useMemo.
✅ Optimize functions with useCallback.
✅ Use stable keys in lists. 🆗