Generate a random file with a specified size

file-gen.js

#!/usr/bin/env node

/* Usage: node file-gen [mb]
 *
 * Example: Generate a 1 GB file
 * $ node file-gen 1024
 * time: 9163.383ms
 */

const fs = require('fs')
const crypto = require('crypto')

const arg = process.argv.slice(2).shift()

const chunkCount = parseInt(arg) || 0
const chunkSize = 1024 * 1024

const stream = fs.createWriteStream(chunkCount + 'mb-random.bytes')

console.time('time')

new Array(chunkCount).fill(void 0).forEach(() =>
  crypto.randomBytes(chunkSize, (_, buffer) =>
    stream.write(buffer)
  )
)

process.on('beforeExit', () => console.timeEnd('time'))