Fisher–Yates 随机排序算法

shuffle.js

/**
 * Fisher–Yates shuffle
 * 
 * https://blog.oldj.net/2017/01/23/shuffle-an-array-in-javascript/
 * https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
 * https://github.com/lodash/lodash/blob/b0980a90fc83bc92e040f905ebed8196f895949c/.internal/shuffleSelf.js
 * @param {array} array 
 */
var shuffle = function (array) {
    var counter = array.length;

    // While there are elements in the array
    while (counter > 0) {
        // Pick a random index
        var index = Math.floor(Math.random() * counter);

        // Decrease counter by 1
        counter--;

        // And swap the last element with it
        var temp = array[counter];
        array[counter] = array[index];
        array[index] = temp;
    }

    return array;
};