react

A set of coding rules for React, a JavaScript library for building user interfaces. It covers components, hooks, state, TypeScript types, and project organization.

In plain words
What is it for?
Use it when creating or reviewing React files such as TypeScript, JavaScript, JSX, and TSX components, hooks, or shared state.
Why use it?
It gives developers consistent ways to structure React code and manage changing data. This can make components easier to reuse, test, and maintain.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/jimmypocock/cursor-rules/react
Clone the repo
git clone --depth 1 https://github.com/jimmypocock/cursor-rules

Made for: Cursor.

Per session 3 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 923 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00003 $0.00923
Opus 5 $0.00002 $0.00462
Sonnet 5 $0.00001 $0.00185
Haiku 4.5 $0.00000 $0.00092

Measured yesterday against content hash 08e36b52f623, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

react scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/react.mdc · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.


Description: React Development Standards Globs: **/.tsx, **/.jsx, */.ts, **/.js, /components//, /hooks//, /context//

React Development Standards

@base.mdc @typescript.mdc

Component Architecture

  • Use functional components with hooks instead of class components
  • Keep components focused on a single responsibility
  • Create small, reusable UI components
  • Implement proper component composition
  • Separate UI components from container components
  • Use proper prop types with TypeScript
  • Structure components with a logical folder organization
  • Create presentational/UI components separate from data containers

Hooks Usage

  • Follow the Rules of Hooks consistently
  • Use useState for component state management
  • Implement useEffect with proper dependencies
  • Create custom hooks for reusable logic
  • Use useCallback for memoized callbacks
  • Implement useMemo for expensive calculations
  • Apply useRef for persisted mutable values
  • Use context hooks for global state access

State Management

  • Use local state for component-specific state
  • Implement React Context for shared state
  • Use proper state management libraries for complex state
  • Keep state normalized and minimal
  • Implement proper state initialization
  • Use state update functions instead of direct assignment
  • Create proper state update patterns
  • Implement state persistence when needed

Performance Optimization

  • Use React.memo for pure components
  • Implement proper key usage in lists
  • Use windowing for long lists (react-window/react-virtualized)
  • Implement proper loading and lazy states
  • Apply code splitting with React.lazy
  • Use Suspense for async operations
  • Implement proper bundle optimization
  • Avoid unnecessary renders with proper dependencies

Event Handling

  • Use proper event handler naming (handleEventName)
  • Implement event handler functions efficiently
  • Use synthetic events properly
  • Apply proper event propagation control
  • Use debouncing/throttling for frequent events
  • Implement proper form submission handling
  • Create controlled components for form elements
  • Apply proper validation for user inputs

Read the full file on GitHub · 143 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 143 lines · 3 tokens per session scan A 08e36b52f623

Subscribe to this mod's changes

react is a cursor rule published in the GitHub repository jimmypocock/cursor-rules (8 stars, last pushed 1y ago), licensed MIT. It adds 3 tokens to every session and 923 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.