JS随机排序数组实现方法分析

function randomOrder (targetArr) {  var originalArr = targetArr;  var newArr = [];  var arrLength = targetArr.length;  var j = -1;  var tmpObj = {};  for(var i = 0;i < arrLength;i++){    while(true) {      if(tmpObj[j = parseInt(arrLength * Math.random())] == undefined) {        tmpObj[j] = 1;        console.log(j);        break;      }    }    newArr[i] = originalArr[j];  }  return newArr;}

function sortNumber(a,b) {  return Math.random() - 0.5;}var arr = arr=[9,3,1,2,5,8,4,7,6,0];arr.sort(sortNumber);