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);