# react-query

This rule guides TanStack Query usage, from cache keys to custom hooks and conditional fetching. Use it as a reference for React projects written in JavaScript or TypeScript.

- rule · `type=rule` · Cursor · ★ 3580
- Author: sanjeed5
- License: CC0-1.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/react-query.mdc
- Updated: 2026-05-19
- HTML: https://affpapa.org/en/nevibecode/rules/react-query

## What it does

The rule covers query keys, custom hooks, query functions, conditional fetching, and data transformations. It recommends array-based keys, moving `useQuery` and `useMutation` logic out of components, and using `enabled` to control when a query runs.

For filtering or reshaping results, it points to `select`; query functions should live apart from components. The rule applies to `**/*.{js,jsx,ts,tsx}`. It provides conventions, not project-specific API calls or types, so those still need to come from your codebase.

## Install

### Cursor (native platform)

**Manually: put the files in place**
- File: `.cursor/rules/react-query.mdc` — Frontmatter: description, globs, alwaysApply

### Claude Code

**Manually: put the files in place**
- File: `.claude/rules/react-query.md` — The paths frontmatter field limits the files: move globs from the source into paths

### Codex

**AGENTS.md**
- Codex reads AGENTS.md: paste the rule text there

### GitHub Copilot

**Manually: put the files in place**
- File: `.github/instructions/react-query.instructions.md` — The applyTo field sets which files it applies to: move globs from the source into applyTo

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/rules/react-query.md`

### Cline

**Manually: put the files in place**
- File: `.clinerules/react-query.md`

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/sanjeed5/awesome-cursor-rules-mdc/tree/HEAD/rules-mdc/react-query.mdc

## When to use it
- structure query keys for caching and filters
- move repeated fetching logic into a custom hook
- run a query only when an identifier exists
- filter and reshape results with `select`

## Example prompts
- Refactor user queries to follow `react-query`, with `useQuery` inside custom hooks.
- Fetch a profile conditionally with `enabled` when `userId` is present.
- Move the active-user filter into `select`.

## Source text · react-query.mdc · CC0-1.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 592943c8594c926d.

BEGIN THIRD-PARTY FILE 592943c8594c926d
````text
---
description: Definitive guidelines for using TanStack Query (formerly React Query) to manage server state efficiently, ensure type safety, and optimize performance in React applications.
globs: **/*.{js,jsx,ts,tsx}
---
# TanStack Query (react-query) Best Practices

This document outlines the definitive best practices for using TanStack Query in our React applications. Adhering to these guidelines ensures consistent, performant, and maintainable data fetching and state management.

## 1. Query Keys: The Foundation of Caching

**ALWAYS** use stable, descriptive array keys. These are fundamental for caching, refetching, and invalidation. For dynamic data, embed parameters directly into the array.

### ✅ GOOD: Stable Array Keys & Key Factories

```typescript
// 1. Simple, static key
const USERS_KEY = ['users'];

// 2. Dynamic key with parameters
const userKeys = {
  all: ['users'] as const,
  lists: () => [...userKeys.all, 'list'] as const,
  list: (filters: { status?: string; page?: number }) =>
    [...userKeys.lists(), { filters }] as const,
  details: () => [...userKeys.all, 'detail'] as const,
  detail: (id: string) => [...userKeys.details(), id] as const,
};

// Usage:
// useQuery(userKeys.all, fetchAllUsers);
// useQuery(userKeys.list({ status: 'active', page: 1 }), fetchUsers);
// useQuery(userKeys.detail(userId), fetchUserById);
```

### ❌ BAD: Unstable or Generic Keys

```typescript
// String keys are less flexible for dynamic data and filtering
useQuery('users', fetchUsers);

// Anonymous object keys are unstable and break caching
useQuery(['users', { id: userId }], fetchUserById); // Object literal creates new reference each render
```

## 2. Custom Hooks: Encapsulate Logic

**ALWAYS** wrap `useQuery` and `useMutation` calls in custom hooks. This centralizes data fetching logic, improves reusability, enhances type safety, and keeps components clean.

### ✅ GOOD: Dedicated Custom Hooks

```typescript
// hooks/useUsers.ts
import { useQuery } from '@tanstack/react-query';
import { fetchUsers, User } from '../api'; // Assume api.ts defines fetchUsers

const userKeys = {
  all: ['users'] as const,
  list: (filters: { status?: string }) => [...userKeys.all, { filters }] as const,
};

export function useUsers(filters?: { status?: string }) {
  return useQuery<User[], Error>({
    queryKey: userKeys.list(filters || {}),
    queryFn: () => fetchUsers(filters),
  });
}

// components/UserList.tsx
import { useUsers } from '../hooks/useUsers';

function UserList({ statusFilter }: { statusFilter?: string }) {
  const { data: users, isLoading, error } = useUsers({ status: statusFilter });

  if (isLoading) return <div>Loading users...</div>;
  if (error) return <div>Error: {error.message}</div>;

  return (
    <ul>
      {users?.map((user) => (
        <li key={user.id}>{user.name}</li>
      ))}
    </ul>
  );
}
```

### ❌ BAD: Direct `useQuery` in Components

```typescript
// components/UserList.tsx
import { useQuery } from '@tanstack/react-query';
import { fetchUsers } from '../api';

function UserList({ statusFilter }: { statusFilter?: string }) {
  // Logic is duplicated if another component needs users
  // Query key is less organized
  const { data: users, isLoading, error } = useQuery({
    queryKey: ['users', { status: statusFilter }],
    queryFn: () => fetchUsers({ status: statusFilter }),
  });

  // ... rest of component
}
```

## 3. Query Functions: Separate and Stable

**NEVER** pass anonymous functions directly to `queryFn`. **ALWAYS** declare `queryFn` separately to ensure stability, prevent unnecessary re-renders, and improve testability.

### ✅ GOOD: Separated Query Functions

```typescript
// api.ts
export async function fetchUserById(id: string): Promise<User> {
  const response = await fetch(`/api/users/${id}`);
  if (!response.ok) throw new Error('Failed to fetch user');
  return response.json();
}

// hooks/useUser.ts
import { useQuery } from '@tanstack/react-query';
import { fetchUserById } from '../api';

const userKeys = {
  detail: (id: string) => ['users', id] as const,
};
````
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