expo-random

What is expo-random?

The expo-random package is a utility for generating cryptographically secure random numbers. It is particularly useful in scenarios where security and unpredictability are crucial, such as in generating tokens, keys, or other secure identifiers.

What are expo-random's main functionalities?

Generating Random Bytes

This feature allows you to generate a specified number of random bytes asynchronously. The example code generates 16 random bytes and logs them to the console.

const { getRandomBytesAsync } = require('expo-random');

(async () => {
  const randomBytes = await getRandomBytesAsync(16);
  console.log(randomBytes);
})();

Generating Random Bytes Synchronously

This feature allows you to generate a specified number of random bytes synchronously. The example code generates 16 random bytes and logs them to the console.

const { getRandomBytes } = require('expo-random');

const randomBytes = getRandomBytes(16);
console.log(randomBytes);

Other packages similar to expo-random

crypto

The 'crypto' module is a built-in Node.js module that provides cryptographic functionality, including a method for generating random bytes. It is similar to expo-random in that it can generate cryptographically secure random numbers, but it is more versatile and widely used in Node.js applications.

randombytes

The 'randombytes' package is a simple wrapper around the Node.js 'crypto' module's randomBytes function. It provides a similar functionality to expo-random, allowing for the generation of cryptographically secure random bytes. It is often used in environments where the full 'crypto' module is not available.

README

expo-random

⚠️ Deprecated

This package is now deprecated in favor of expo-crypto, which provides the same functionality. To migrate, replace all imports from expo-random with imports from expo-crypto.

Provides a native interface for creating strong random bytes. With Random you can generate random values to address use cases that other APIs like the web's crypto.getRandomValues and Node's crypto.randomBytes might address.

Installation in managed Expo projects

For managed Expo projects, please follow the installation instructions in the API documentation for the latest stable release.

You can add a polyfill for the web's crypto.getRandomValues by installing expo-standard-web-crypto and importing it in SDK 39 and higher:

import { polyfillWebCrypto } from 'expo-standard-web-crypto';

polyfillWebCrypto();
// crypto.getRandomValues is now globally defined

Other libraries like react-native-get-random-values may work too.

Installation in bare React Native projects

For bare React Native projects, you must ensure that you have installed and configured the expo package before continuing.

Add the package to your npm dependencies

npx expo install expo-random

Configure for iOS

Run npx pod-install after installing the npm package.

Configure for Android

No additional set up necessary.