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infinite-canvas/.agents/skills/vercel-react-best-practices/rules/rerender-memo.md
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HouYunFei fb79a15508 docs(vercel-react-best-practices): 添加 Vercel React 最佳实践规则文档
- 添加 sections 定义文件,包含性能优化各领域分类
- 添加规则模板文件,规范文档结构和标签定义
- 添加异步操作优化规则,包括防止瀑布流、并行化、延迟等待等
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- 添加服务端性能优化规则,包括 API 路
2026-05-21 15:22:11 +08:00

1.1 KiB

title, impact, impactDescription, tags
title impact impactDescription tags
Extract to Memoized Components MEDIUM enables early returns rerender, memo, useMemo, optimization

Extract to Memoized Components

Extract expensive work into memoized components to enable early returns before computation.

Incorrect (computes avatar even when loading):

function Profile({ user, loading }: Props) {
  const avatar = useMemo(() => {
    const id = computeAvatarId(user)
    return <Avatar id={id} />
  }, [user])

  if (loading) return <Skeleton />
  return <div>{avatar}</div>
}

Correct (skips computation when loading):

const UserAvatar = memo(function UserAvatar({ user }: { user: User }) {
  const id = useMemo(() => computeAvatarId(user), [user])
  return <Avatar id={id} />
})

function Profile({ user, loading }: Props) {
  if (loading) return <Skeleton />
  return (
    <div>
      <UserAvatar user={user} />
    </div>
  )
}

Note: If your project has React Compiler enabled, manual memoization with memo() and useMemo() is not necessary. The compiler automatically optimizes re-renders.