js-hoist-regexp

Don't create RegExp inside render. Hoist to module scope or memoize with useMemo().

Skills
Web development
3

What it does and how to use it

A skill that teaches Claude Code to do web development tasks well. It is packaged knowledge the model uses whenever it is relevant.

Install the skill (command above).
In Claude Code, describe what you need - the skill turns on by itself when the context fits.
No commands to memorize: you talk in plain language and the skill does the rest.

Install (Claude Code)

mkdir -p .claude/skills/js-hoist-regexp && curl -fsSL https://doutorai.pt/data/lib/skills__js-hoist-regexp.md -o .claude/skills/js-hoist-regexp/SKILL.md

Paste this command into the terminal, in your project folder, and the component installs automatically.

Content

---
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({ 

- 🔒 Full content on the Pro plan (€7.99/month) -

Need help with Claude Code?

Ask Dr AI - it explains things simply.

Need a tailor-made solution?

Not sure where to start with AI in your business? Get a free assessment and a tailored plan - no commitment.

Save hours every week with AI, no hassle

Doutor AI gives you 1,859 ready-to-copy AI prompts, by industry and in plain English - plus a complete technical library for those who want to go further.

See plans