比較兩個Json對象是否相等

一個前端同事遇到的面試題，抽空寫了寫，也算是個積累

1.先準備三個工具方法，用於判斷是否是對象類型，是否是數組，獲取對象長度

 1     function isObj(object) {
 2         return object && typeof (object) == 'object' && Object.prototype.toString.call(object).toLowerCase() == "[object object]";
 3     }
 4 
 5     function isArray(object) {
 6         return object && typeof (object) == 'object' && object.constructor == Array;
 7     }
 8 
 9     function getLength(object) {
10         var count = 0;
11         for (var i in object) count++;
12         return count;
13     }

2.準備兩個相同或不同的Json對象

 1    var jsonObjA = {
 2         "Name": "MyName",
 3         "Company": "MyCompany",
 4         "Infos": [
 5              { "Age": "100" },
 6              {
 7                  "Box": [
 8                     { "Height": "100" },
 9                     { "Weight": "200" }
10                  ]
11              }
12         ],
13         "Address": "馬欄山"
14     }
15     var jsonObjB = {
16         "Name": "MyName",
17         "Company": "MyCompany",
18         "Infos": [
19             { "Age": "100" },
20             {
21                 "Box": [
22                     { "Height": "100" },
23                     { "Weight": "200" }
24                 ]
25             }
26         ],
27         "Address": "馬欄山二號"
28     }

3.主要的代碼

 1     function Compare(objA, objB) {
 2         if (!isObj(objA) || !isObj(objB)) return false; //判斷類型是否正確
 3         if (getLength(objA) != getLength(objB)) return false; //判斷長度是否一致
 4         return CompareObj(objA, objB, true);//預設為true
 5     }
 6 
 7     function CompareObj(objA, objB, flag) {
 8         for (var key in objA) {
 9             if (!flag) //跳出整個迴圈
10                 break;
11             if (!objB.hasOwnProperty(key)) { flag = false; break; }
12             if (!isArray(objA[key])) { //子級不是數組時,比較屬性值
13                 if (objB[key] != objA[key]) { flag = false; break; }
14             } else {
15                 if (!isArray(objB[key])) { flag = false; break; }
16                 var oA = objA[key], oB = objB[key];
17                 if (oA.length != oB.length) { flag = false; break; }
18                 for (var k in oA) {
19                     if (!flag) //這裡跳出迴圈是為了不讓遞歸繼續
20                         break;
21                     flag = CompareObj(oA[k], oB[k], flag);
22                 }
23             }
24         }
25         return flag;
26     }

4.調用方法

1   var result = Compare(jsonObjA, jsonObjB);
2   console.log(result); // true or false