The Missing Native Fetch for Expo

Use the power of native networking libraries with a standard fetch API.
Handle cookies and redirects with ease.

Installation · Usage · API Reference · Contributing

---

🌟 Why Expo Fetcher?

expo-fetcher bridges the gap between the JavaScript fetch API and native networking capabilities ensuring your apps are robust, secure, and performant.

Feature	Description
🍪 Advanced Cookie Support	Persistent cookie jar on Android. Full visibility of Set-Cookie headers on iOS.
⚡ Native Networking	Uses platform-native networking stacks (NSURLSession/OkHttp) for maximum reliability.
⤵️ Smart Redirects	Fine-grained control over redirect policies: follow, error, or manual.
✨ Standard API	Drop-in replacement for fetch. No new concepts to learn.
🔒 Type Safe	Written in TypeScript with complete definitions included.

📦 Installation

Add the package to your Expo or React Native project.

# Using npm
npm install expo-fetcher

# Using yarn
yarn add expo-fetcher

# Using expo
npx expo install expo-fetcher

🛠 Usage

Basic Fetch

It works just like the standard fetch you know and love.

import { fetch } from 'expo-fetcher';

// Simple GET request
const response = await fetch('https://api.example.com/data');
const json = await response.json();

Advanced POST with Headers

import { fetch } from 'expo-fetcher';

const uploadData = async () => {
  try {
    const response = await fetch('https://api.example.com/users', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': 'Bearer <YOUR_TOKEN>',
      },
      body: JSON.stringify({ name: 'John Doe', role: 'Developer' }),
    });

    if (response.ok) {
      console.log('Success:', await response.json());
    }
  } catch (error) {
    console.error('Request failed:', error);
  }
};

Cookie Management

Authentication cookies set by the server are automatically stored and managed on Android. On iOS, you have full access to Set-Cookie headers to manage sessions manually if needed.

Note: Android maintains a persistent cookie jar between requests. iOS requests use isolated sessions, so cookies are not automatically carried over to subsequent requests.

import { clearCookies } from 'expo-fetcher';

const handleLogout = async () => {
  // Clears the native cookie storage (Android only)
  await clearCookies();
  console.log('Session cleared');
};

📚 API Reference

fetch(input, init)

Performs a network request.

Parameter	Type	Required	Description
input	string | URL | Request	✅	The URL or Request object.
init	RequestInit	❌	Optional configuration object.

RequestInit Options

Option	Type	Default	Description
method	'GET' | 'POST' | 'PUT' | 'DELETE' | 'PATCH' | 'HEAD' | 'OPTIONS'	'GET'	The HTTP method to use.
headers	Headers | Record<string, string>	{}	Request headers.
body	string | ArrayBuffer | Uint8Array	undefined	The body content.
redirect	'follow' | 'error' | 'manual'	'follow'	Redirect handling policy.

clearCookies()

Clears all cookies stored in the native container.

Return Type	Description
Promise<void>	Resolves when the Android cookie jar has been emptied.

🤝 Contributing

We welcome contributions! Please see the guidelines below.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📄 License

This project is licensed under the MIT License.