Random

expo-random provides a native interface for creating strong random bytes. With Random you can create values equivalent to Node.js core crypto.randomBytes API.

Platform Compatibility

Android Device	Android Emulator	iOS Device	iOS Simulator	Web
✅	✅	✅	✅	✅

Installation

expo install expo-random

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Usage

import React from 'react';
import { View } from 'react-native';
import * as Random from 'expo-random';

export default class DemoView extends React.Component {
  async componentDidMount() {
    const randomBytes = await Random.getRandomBytesAsync(16);

    /* Some crypto operation... */
  }
  render() {
    return <View />;
  }
}

API

import * as Random from 'expo-random';

Methods

`Random.getRandomBytesAsync(byteCount)`

getRandomBytesAsync(byteCount: number): Promise<Uint8Array>

Generates completely random bytes using native implementations. The byteCount property is a number indicating the number of bytes to generate in the form of a Uint8Array.

Parameters

Name	Type	Description
byteCount	`number`	A number within the range: 0...1024. Anything else will throw a `TypeError`

Returns

Name	Type	Description
randomBytes	`Promise<Uint8Array>`	An array of random bytes with the same length as the `byteCount`

Example

const randomBytes = await Random.getRandomBytesAsync(3);