JS code to compare the value of adding and deleting the old and new arrays_javascript skills

Copy code The code is as follows:

I used the one I wrote in the previous project. There should be no bugs. If there is a better one, everyone is welcome to give me advice.
var Return_AddStrFn=function (oldArr, newArr) {
var t = this;
　　　　　　　　　　　　　　　 Array.prototype.unique4 = function () {
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 hands through through Array.prototype.unique4 = function () {
          var temp = new temp = new Array(); ;
for (i = 0; i < this.length; i ) {
if (this[i] == this[i 1]) {
continue;
}
temp[temp.length] = this[i];
                                                                                                                                                                                                                                                                                . e = newArr.unique4();//New array
var c = [];
var dels = [];
function f() {
a.sort();
b.sort();
var i = 0;
var j = 0;
while (i < a.length && j < b.length) {
if (a[i ] < b[j]) {
                                                                      c .push(b[j]);
                                                                                                                                                                                                                                                                                                                             through {
                                                                                                                   c.push(b[j]);
           j;
         f();
         //alert("c:" c);
         //alert("d:" d);
        var addstr = [];
        for (var i = 0; i < c.length; i ) {
           for (var j = 0; j < e.length; j ) {
             if (e[j] == c[i]) {
                  addstr.push(e[j]);
              }
            }
        }
        return addstr; //新增的
        //for (var i = 0; i < c.length; i ) {
        //    for (var j = 0; j < d.length; j ) {
        //        if (d[j] == c[i]) {
        //           del.push(d[j]);
        //        }
        //    }
         }
        //alert("of:" of); //删除的
     }

调用方式: var arr = [1, 2,2,3, 3, 4, 5];
             var arr2=[1,2,2, 5]

       var addStr=Return_AddStrFn(arr2,arr);