例子

1.将数组 [1,2,3,4,5,6,7,8,9]转换为[[1,2,3],[4,5,6],[7,8,9]]

var arr=[1,2,3,4,5,6,7,8,9];
var sum =[];
        for(var i=0;i<arr.length;i=i+3){
             var item = arr.slice(i,i+3);
             sum.push(item);
        }
        console.log(sum)

2.将字符串”hello”转换为olleh

/ [h,e,l,l,o] /
// [o,l,l,e,h]
// olleh

 var str="hello";
        var arr=str.split("");
        arr.reverse();
         var s=arr.join("");
        console.log(s);

3.

将”https://192.168.4.18?lmit=20&offset=0“切割为
[{limit:20},{offset:0}]

   var http = "https://192.168.4.18?limit=20&offset=0"
        //[{limit:20},{offset:0}]
        var arr = http.split("?")[1].split("&");
        //["limit=20", "offset=0"]
        var res = arr.map(item=>{
            var obj = {};
            obj[item.split("=")[0]] = item.split("=")[1];
            //item = [limit,20]
            return obj;
        })
        console.log(res)

将字符串切割为{limit:20,offset:0}

 <script>
         var http="https://192.168.4.18?lmit=20&offset=0";
            //{limit:20,offset:0}
         var arr=http.split("?")[1].split("&")
         var obj={};
        var res=arr.map(item=>{
            obj[item.split("=")[0]]=item.split("=")[1]
            // return obj;
        })      
        console.log(obj);
  </script>