Crypto

`crypto.getRandomValues`

Fills the provided typed array with cryptographically strong random values

Syntax

JavaScript

crypto.getRandomValues(typedArray)

Parameters

Parameter	Type	Description
typedArray	TypedArray	An integer-based TypedArray to fill with random values

Return Value

The same typed array passed in, now filled with random values

Examples

Basic Usage

const array = new Uint8Array(16)
crypto.getRandomValues(array)
console.log(array)

Practical Example

function randomInt(min: number, max: number): number {
  const range = max - min
  const array = new Uint32Array(1)
  crypto.getRandomValues(array)
  return min + (array[0] % range)
}

Advanced Usage

function generateToken(length: number): string {
  const bytes = new Uint8Array(length)
  crypto.getRandomValues(bytes)
  return Array.from(bytes, b => b.toString(16).padStart(2, '0')).join('')
}

Understanding crypto.getRandomValues

The crypto.getRandomValues method in JavaScript fills the provided typed array with cryptographically strong random values. It belongs to the Crypto object and is one of the most widely used methods for working with crypto values in modern JavaScript and TypeScript applications.

The method signature is crypto.getRandomValues(typedArray). It accepts 1 parameter: typedArray. When called, it returns the same typed array passed in, now filled with random values. Understanding when and how to use getRandomValues() helps you write more expressive, readable code.

Common use cases for crypto.getRandomValues include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like crypto-randomuuid, math-random, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for crypto.getRandomValues is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.