javascript数组对象问题

Question

我有下面的JSON响应。我使用$ .getJSON方法来加载JSON数据，并使用回调函数通过检查它是否为数组来执行一些操作。

{ 
    "r": [{ 
     "IsDefault": false, 
     "re": { 
      "Name": "Depo"    
     }, 
     "Valid": "Oct8, 2013", 
     "Clg": [{ 
      "Name": "james", 
      "Rate": 0.05 
     }, { 
      "Name": "Jack", 
      "Rate": 0.55 
     }, { 
      "Name": "Mcd", 
      "Rate": 0.01, 
     }], 
    }, 
    { 
     "IsDefault": false, 
     "re": { 
      "Name": "Depo" 
     }, 
     "Valid": "Oct8, 2013", 
     "Clg": [{ 
      "Name": "james", 
      "Rate": 0.05 
     }, { 
      "Name": "Jack", 
      "Rate": 0.55 
     }, { 
      "Name": "Mcd", 
      "Rate": 0.01, 
     }], 
    }, 
    { 
     "IsDefault": false, 
     "re": { 
      "Name": "Depo" 
     }, 
     "Valid": "Oct8, 2013", 
     "Clg": [{ 
      "Name": "james", 
      "Rate": 0.05 
     }, { 
      "Name": "Jack", 
      "Rate": 0.55 
     }, { 
      "Name": "Mcd", 
      "Rate": 0.01, 
     }], 
    }] 
} 

我从两loadFromJson1和loadFromJson2功能为“输入”的JSON响应为参数如下。

var tablesResult = loadFromJson1(resultstest.r[0].Clg); 
    loadFromJson1 = function (input) { 
     if (_.isArray(input)) { 
     alert("loadFromJson1: Inside array function"); 
      var collection = new CompeCollection(); 
      _.each(input, function (modelData) { 
       collection.add(loadFromJson1(modelData)); 
      }); 
      return collection; 
     } 
     return new CompeModel({ 
      compeRates: loadFromJson2(input), 
      compName: input.Name 
     }); 
    }; 

    loadFromJson2 = function (input) 
    // here is the problem, the 'input' is not an array object so it is not going to IF condition of the isArray method. 
    { 
     if (_.isArray(input)) { 
      alert("loadFromJson2: Inside array function"); 
      //alert is not coming here though it is an array 
      var rcollect = new rateCollection(); 
      _.each(input, function (modelData) { 
       rcollect.add(modelData); 
      }); 
      return rcollect; 
     } 
    }; 

上面的代码我传递json响应为loadFromJson1和loadFromJson2函数作为“输入”。 isArray只在loadFromJson1函数中获得true，并在if条件中给出警报，但是不在loadFromJson2函数中，尽管我传递的是相同的参数。

任何人都可以告诉我为什么loadFromJson2函数没有得到内部警报如果条件虽然我传递数组对象？

Answer 1

如果input是数组，则不调用loadFromJson2。只有在input是而不是的数组时才会调用它。因此在loadFromJson2内_.isArray(input)将永远不会成立。

Here's a jsfiddle演示它（打开浏览器的JavaScript控制台查看日志）。你得到这个输出从输入：

into loadFromJson1 call #1 (index):82 
loadFromJson1 #1: it's an Array (index):84 
loadFromJson1 #1: Inside array function (index):85 
into loadFromJson1 call #2 (index):82 
loadFromJson1 #2: not an array (index):93 
loadFromJson1 #2: calling loadFromJson2 and returning (index):95 
into loadFromJson2 (index):105 
loadFromJson2: not an array (index):115 
into loadFromJson1 call #3 (index):82 
loadFromJson1 #3: not an array (index):93 
loadFromJson1 #3: calling loadFromJson2 and returning (index):95 
into loadFromJson2 (index):105 
loadFromJson2: not an array (index):115 
into loadFromJson1 call #4 (index):82 
loadFromJson1 #4: not an array (index):93 
loadFromJson1 #4: calling loadFromJson2 and returning (index):95 
into loadFromJson2 (index):105 
loadFromJson2: not an array (index):115 
loadFromJson1 #1: returning (index):90 

正如你所看到的，到loadFromJson2的电话是从嵌套调用loadFromJson1 - 那得到的东西，是不是一个阵的人。