Poor man's UUID

baduuid.js

/**
 * This is NOT a cryptographically strong UUID algorithm
 * It is purely for quick-n-easy drag-n-drop scripting applications where
 * data quality does not matter.
 *
 * For a proper UUID implementation, see
 * https://github.com/uuidjs/uuid/blob/master/src/v4.js
 */
const max = Math.pow(2, 8) - 1
// this slick trick thanks to https://github.com/uuidjs/uuid/blob/e8cb0a03a5408415d1f93a1499d8cda47246adc7/src/bytesToUuid.js#L7
// this avoids having to manually add a `0` to hex values with only 1 char
const toHex = n => (n + 0x100).toString(16).substr(1)
const adjust = (n, min, max) => Math.round(n * (max - min) + min)
const rand8bit = () => adjust(Math.random(), 0, max)
const rand8bitHex = () => toHex(rand8bit())
const repeatHex = n => Array(n).fill(0).map(() => rand8bitHex()).join('')
const uuid = () => [repeatHex(4), repeatHex(2), repeatHex(2), repeatHex(2), repeatHex(6)].join('-')