How to use window.crypto.getRandomValues to get random values in a specific range

Question

We had been using Math.random to get random numbers between 4000-64000.:

Math.floor(Math.random() * 60000 + 4000);

We have to now replace this

Answer 1

A simple replacement for Math.random might look like this:

/**
 * Return values in the range of [0, 1)
 */
const randomFloat = function () {
  const int = window.crypto.getRandomValues(new Uint32Array(1))[0]
  return int / 2**32
}

To extend this to integers:

/**
 * Return integers in the range of [min, max)
 *
 * @todo check that min is <= max.
 */
const randomInt = function (min, max) {
  const range = max - min
  return Math.floor(randomFloat() * range + min)
}

To extend this to arrays of integers:

/**
 * Generate an array of integers in the range of [min, max).
 */
const randomIntArray = function (length, min, max) {
  return new Array(length).fill(0).map(() => randomInt(min, max))
}

Generate an array of ten integers from 0 to 2 inclusive:

randomIntArray(10, 0, 3)

[0, 2, 1, 2, 0, 0, 1, 0, 1, 0]