Stress test helpers for arrays

arrayTester.js

/**
 * @description Generate indexes used to access an array.
 * @param {number} len Length of the array
 * @param {number} [bound=1] How much the boundaries needs to be extended by
 * @param {number} [mult=1] How the resulting array of index needs to be multiplied by
 * @returns {number[]} Array of indexes
 * @example
 * let arr = ['lorem', 'ipsum', 'dolore'];
 * genIdxs(arr.length); //[-4, -3, -2, -1, 0, 1, 2, 3, 4]
 * genIdxs(arr.length, 2); //[-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5]
 * genIdxs(arr.length, 1, 2); //[-8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8]
 */
const genIdxs = (len, bound = 1, mult = 1) => {
  let res = [],
      HB = (len + bound) * mult;
  for (let i = -HB; i <= HB; ++i) res.push(i);
  return res;
}