mARTin
d92a8c7210
- Added 'onDelete' and 'onNotes' support to TaskItem. - Implemented hover actions (Delete and Notes icons) for tasks. - Added Notes Modal for editing task markdown content. - Simplified navigation animation to remove blank flash (single-phase slide-in). - Fixed syntax error in updateTask function. - Updated styles for modal and task actions.
30 lines
728 B
Markdown
30 lines
728 B
Markdown
---
|
|
title: Subscribe to Derived State
|
|
impact: MEDIUM
|
|
impactDescription: reduces re-render frequency
|
|
tags: rerender, derived-state, media-query, optimization
|
|
---
|
|
|
|
## Subscribe to Derived State
|
|
|
|
Subscribe to derived boolean state instead of continuous values to reduce re-render frequency.
|
|
|
|
**Incorrect (re-renders on every pixel change):**
|
|
|
|
```tsx
|
|
function Sidebar() {
|
|
const width = useWindowWidth() // updates continuously
|
|
const isMobile = width < 768
|
|
return <nav className={isMobile ? 'mobile' : 'desktop'} />
|
|
}
|
|
```
|
|
|
|
**Correct (re-renders only when boolean changes):**
|
|
|
|
```tsx
|
|
function Sidebar() {
|
|
const isMobile = useMediaQuery('(max-width: 767px)')
|
|
return <nav className={isMobile ? 'mobile' : 'desktop'} />
|
|
}
|
|
```
|