ES6 判定两个数组是否相同

 1     private isEqual(a:number[], b:number[]): boolean{
 2         if(!a|| !b) {
 3             return false;
 4         } else {
 5             if(a.length != b.length){
 6                 return false;
 7             }else{
 8                 if(a.length==0){
 9                     return true;
10                 } else {
11                     for (let x = 0; x < a.length; x++) {
12                         let aa = a[x];
13                         if(b.indexOf(aa)==-1){
14                             return false;
15                         }           
16                     }
17                     return true;
18                 }
19             }
20         }
21     }