shuffle.js

;
/**
 * 要求，种子相同的情况下返回的随机序列数组相同。
 * e.g.
 *  <= (1477044467806, 4)
 *  => [3, 2, 0, 1]
 *
 *  <= (1477044467886, 6)
 *  => [3, 4, 2, 5, 0, 1]
 * @param seed 随机数种子
 * @param length 序列长度
 */
function shuffle(length, seed) {
    if (!seed) seed = Date.now();
    var sort = [];
    var temp, j;
    for (var i = 0; i < length; i++) {
        j = (seed % (i + 1) + i) % length;

        temp = sort[i] || i;
        sort[i] = sort[j] || j;
        sort[j] = temp;
    }
    return sort;
}