[Suggestion]: Clarify restrictions on rendering <html> and <body> tags inside the component tree to prevent infinite loops in React 19
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- 主要語言
- JavaScript
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- 1 天 11 小時
- 30 天內合併 PR
- 11
描述
Summary
Add an explicit warning to the React 19 Upgrade Guide and Metadata documentation stating that <html> and <body> tags are not supported for native hoisting. Clarify that rendering these tags inside a createRoot tree causes a terminal infinite loop (browser freeze) during event propagation (e.g., input focus), especially since many developers are currently migrating away from react-helmet to React 19's native metadata handling.
Page
https://react.dev/blog/2024/04/25/react-19-upgrade-guide
Details
In React 19, rendering an <html> or <body> tag within a custom component tree (nested under a createRoot container) causes a critical browser freeze (100% CPU usage) due to this issue#35480.
I encountered this issue while refactoring an existing application to remove the react-helmet dependency. With the introduction of Metadata Hoisting, it seemed logical to replace library-managed tags with native JSX tags. However, while React 19 successfully hoists <title>, <meta>, and <link>, it fails to handle <html> or <body> in the same way. Instead of a warning or a graceful fallback, it results in a terminal infinite loop during event propagation (e.g., when clicking an input).
For example, I replaced my existing react-helmet logic with a direct JSX tag, expecting React to manage the lang attribute:
// This refactoring caused the terminal hang:
<Wrap>
{/* I moved this out of <Helmet> thinking it was now supported natively */}
<html lang={locale} />
<Content>{children}</Content>
</Wrap>
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研究方向
從連結頁面上的 React 19 Upgrade Guide 開始，找到 Metadata 文件部分。新增明確的警告，說明 和 不支援 native hoisting，在 createRoot 樹中 render 時可能導致無限迴圈；對於從 react-helmet 遷移的開發者來說，只要這項限制和瀏覽器凍結的風險都清楚，就算完成。
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評估
- 技術堆疊
- react
- 領域
- documentation
- Issue 類型
- 文件
- 難度
- 2/5
- 預估耗時
- 1-3 小時
- 活躍度
- 冷清
- 描述清晰度
- 描述清楚
- 新手友好度
- 68/100