数组技巧

• 数组随机打乱

var arr = [47, 16, 35, 90, 81, 10, 59, 84, 61, 13, 94, 74, 43, 87]；
randomArr = arr.sort(function(){ return 0.5 - Math.random() })

• 伪数组转成数组

伪数组arrayLike，必须按照索引存储，具有length属性，缺少数组的push,pop等方法

var arrayLike = {
    0: "a",
    1: "b",
    2: "c",
    3: "d",
    length:4
};

方法一
var arr1 = Array.prototype.slice.call(arrayLike);
方法二
和方法一性质一样且方法一效率更高
var arr2 = [].slice.call(arrayLike);
方法三
ES6中Array.from方法
var arr3 = Array.from(arrayLike);

• 数组内对象排序

var arr = [{aa: 22, zIndex: 2},{aa: 33, zIndex: 3},{aa: 11, zIndex: 1},{aa: 55, zIndex: 5}];
var tem = [];
var arrCopy = [...Array(arr.length).keys()].map((item) => { return item });
arr.forEach((v,i)=>{
  tem.push(v.zIndex)
})
tem.sort((v1,v2)=>{ return v1 - v2 });

arr.forEach((value,item)=>{
  var nowIndex;
  var newValue;
  tem.forEach((v,i)=>{
    if(value.zIndex === v){
      nowIndex = i;
    }
  });
  arrCopy[nowIndex] = value;
});
console.log(arrCopy)

• 数组去重

var arr = [{a:1},1,2,3,1,2,3,{a:1},{a:'1'}];
var newArr = Array.from(new Set(arr.map(item => JSON.stringify(item)))).map(item => JSON.parse(item));