[JS] Simple Math Functions (without class)

MMath.js

const MMath = {
  /**
   * Return a random integer N such that `a <= N <= b`.

   * @param {Number} a
   * @param {Number} b
   * @returns {Number}
   */
  randint: function (a, b) {
    const min = b != undefined ? a : 0;
    const max = b != undefined ? b : a;

    return Math.floor(Math.random() * (max - min) + min);
  },

  /**
   * Return a random element from the non-empty sequence seq
   *
   * @param {Array} array
   * @returns {*}
   */
  choice: function (array) {
    return array[this.randint(array.length)];
  },

  /**
   * Description placeholder
   *
   * @param {Array} array
   * @param {Number} k
   * @returns {Array}
   */
  choices: function (array, k) {
    const newArray = [];
    for (let i = 0; i < k; i++)
      newArray.push(array[this.randint(array.length)]);
    return newArray;
  },

  /**
   * Return a *k* length list of unique elements chosen from the population sequence. Used for random sampling without replacement.
   *
   * @param {Array} array
   * @param {Number} k
   * @returns {Array}
   */
  sample: function (array, k) {
    const oldArray = array.slice();
    const newArray = [];
    const sampleTimes = k != undefined ? k : array.length;
    let index
    for (let i = 0; i < sampleTimes; i++) {
      index = this.randint(oldArray.length);
      newArray.push(oldArray[index]);
      oldArray.splice(index, 1);
    }
    return newArray;
  },
};