ShuffleAnArray.js

// Source : https://leetcode.com/problems/shuffle-an-array
// Author : Dean Shi
// Date   : 2017-09-05

/***************************************************************************************
 *
 * Shuffle a set of numbers without duplicates.
 *
 * Example:
 *
 * // Init an array with set 1, 2, and 3.
 * int[] nums = {1,2,3};
 * Solution solution = new Solution(nums);
 *
 * // Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must
 * equally likely to be returned.
 * solution.shuffle();
 *
 * // Resets the array back to its original configuration [1,2,3].
 * solution.reset();
 *
 * // Returns the random shuffling of array [1,2,3].
 * solution.shuffle();
 *
 *
 ***************************************************************************************/

/**
 * @param {number[]} nums
 */
var Solution = function(nums) {
    this.nums = nums
};

/**
 * Resets the array to its original configuration and return it.
 * @return {number[]}
 */
Solution.prototype.reset = function() {
    return this.nums
};

/**
 * Returns a random shuffling of the array.
 * @return {number[]}
 */
Solution.prototype.shuffle = function() {
    let i, count = this.nums.length, nums = this.nums.slice()

    while (count) {
        i = Math.floor(Math.random() * count--);
        [nums[i], nums[count]] = [nums[count], nums[i]]
    }
    return nums
};

/**
 * Your Solution object will be instantiated and called as such:
 * var obj = Object.create(Solution).createNew(nums)
 * var param_1 = obj.reset()
 * var param_2 = obj.shuffle()
 */