mirror of
https://github.com/kjanat/livedash-node.git
synced 2026-02-13 12:55:42 +01:00
Kaj Kowalski
5bfd762e55
- Update tsconfig to ES2024 target and bundler moduleResolution - Add dynamic imports for chart.js and recharts (bundle optimization) - Consolidate 17 useState into useReducer in sessions page - Fix 18 .js extension imports across lib files - Add type declarations for @rapideditor/country-coder - Fix platform user types (PlatformUserRole enum) - Fix Calendar component prop types - Centralize next-auth type augmentation - Add force-dynamic to all API routes (prevent build-time prerender) - Fix Prisma JSON null handling with Prisma.DbNull - Fix various type mismatches (SessionMessage, ImportRecord, etc.) - Export ButtonProps from button component - Update next-themes import path - Replace JSX.Element with React.ReactElement - Remove obsolete debug scripts and pnpm lockfile - Downgrade eslint to v8 for next compatibility
46 lines
1.0 KiB
Markdown
46 lines
1.0 KiB
Markdown
---
|
|
title: Hoist RegExp Creation
|
|
impact: LOW-MEDIUM
|
|
impactDescription: avoids recreation
|
|
tags: javascript, regexp, optimization, memoization
|
|
---
|
|
|
|
## Hoist RegExp Creation
|
|
|
|
Don't create RegExp inside render. Hoist to module scope or memoize with `useMemo()`.
|
|
|
|
**Incorrect (new RegExp every render):**
|
|
|
|
```tsx
|
|
function Highlighter({ text, query }: Props) {
|
|
const regex = new RegExp(`(${query})`, 'gi')
|
|
const parts = text.split(regex)
|
|
return <>{parts.map((part, i) => ...)}</>
|
|
}
|
|
```
|
|
|
|
**Correct (memoize or hoist):**
|
|
|
|
```tsx
|
|
const EMAIL_REGEX = /^[^\s@]+@[^\s@]+\.[^\s@]+$/
|
|
|
|
function Highlighter({ text, query }: Props) {
|
|
const regex = useMemo(
|
|
() => new RegExp(`(${escapeRegex(query)})`, 'gi'),
|
|
[query]
|
|
)
|
|
const parts = text.split(regex)
|
|
return <>{parts.map((part, i) => ...)}</>
|
|
}
|
|
```
|
|
|
|
**Warning (global regex has mutable state):**
|
|
|
|
Global regex (`/g`) has mutable `lastIndex` state:
|
|
|
|
```typescript
|
|
const regex = /foo/g
|
|
regex.test('foo') // true, lastIndex = 3
|
|
regex.test('foo') // false, lastIndex = 0
|
|
```
|