使用Javascript - 從另一個陣列

查找子陣的價值，我有兩個JavaScript對象：使用Javascript - 從另一個陣列

var classroom = { 
    "number" : "1", 
    "student" : [ 
     { 
     "number" : 1, 
     "items" : [ 
      { 
      "key" : "00000000000000000000001C", 
      "date" : "2016-04-21T17:35:39.997Z" 
      } 
     ] 
     }, 
     { 
     "number" : 2, 
     "items" : [ 
      { 
      "key" : "00000000000000000000001D", 
      "date" :"2016-04-21T17:35:39.812Z" 
      }, 
      { 
      "key" : "00000000000000000000002N", 
      "date" :"2016-04-21T17:35:40.159Z" 
      }, 
      { 
      "key" : "00000000000000000000002Ñ", 
      "date" :"2016-04-21T17:35:42.619Z" 
      } 
     ] 
     } 
    ], 
    }

和

var items = [ 
    { 
    "fields" : { 
     "tags" : [ 
     { 
      "key" : "00000000000000000000001C", 
      "Batch" : "50", 
      "Bin" : "01", 
      "Tray" : "02" 
     }, 
     { 
      "key" : "00000000000000000000002N", 
      "Batch" : "55", 
      "Bin" : "05", 
      "Tray" : "12" 
     }, 
     { 
      "key" : "000000000000228510000032", 
      "Batch" : "12", 
      "Bin" : "12", 
      "Tray" : "01" 
     } 
     ], 
     "Name" : "Rubber" 
    }, 
    "_id" : "56d19b48faa37118109977c0" 
    }, 
    { 
    "fields" : { 
     "tags" : [ 
     { 
      "key" : "00000000000000000000001D", 
      "Batch" : "50", 
      "Bin" : "01", 
      "Tray" : "05" 
     }, 
     { 
      "key" : "00000000000000000000002Ñ", 
      "Batch" : "52", 
      "Bin" : "07", 
      "Tray" : "02" 
     }, 
     { 
      "key" : "221567010000000000000089", 
      "Batch" : "11", 
      "Bin" : "15", 
      "Tray" : "03" 
     } 
     ], 
     "Name" : "Book" 
    }, 
    "_id" : "56d19b48faa37118109977c1" 
    } 
];

好吧，我需要創建一個貫穿各個item每student去功能在classroom變量。對於每個item，我需要在items陣列中找到與tags中的一個具有完全相同的key的對象。

我的代碼也越來越奇怪的結果... missmatching項目...

var finalitems = []; 

classroom.student.forEach(function (student){ 
    student.items.forEach(function (obj){ 

    items.forEach(function (theitem){ 
     theitem.fields.tags.forEach(function (tag){ 

     if (tag.key === obj.key) { 

      var newitem = theitem; 
      newitem.tag = obj; 
      finalitems.push(newitem);  
     } 
     }); 
    });   
    }); 
});

我知道的foreach是一種指針，但我真的不明白爲什麼它正在奇怪，以及它如何需要被完成。

問候，

來源

2016-04-21 Egidi

創建工作片段。定義「奇怪的結果」。 – Amit

https://jsfiddle.net/ynqtjL3d/請找出每件物品的標籤不是它應該是什麼。當應該有4個項目但每個具有不同的標籤密鑰（00000000000000000000001C，00000000000000000000001D，00000000000000000000002N，00000000000000000000002N）時，我可以看到4個項目（正確），但有兩個項目帶有標籤密鑰「00000000000000000000002Ñ」，另外兩個帶有標籤密鑰「00000000000000000000002N」） – Egidi

請添加結果應該如何。 –

JavaScript的變量只保存對象引用，而不是在內存中的實際對象，所以這行：

var newitem = theitem;

指的newitem指的是同一個對象theitem，不能創建新對象來自這個項目。

所以

newitem.tag = obj;

相同

theitem.tag = obj;

這意味着你正在修改的輸入對象，這就是爲什麼你不會得到預期的輸出。

要得到你需要創建theitem的副本，並指定該對象的newitem變量所需的行爲：

var newitem = Object.create(theitem);

來源

2016-04-21 18:45:46 WorldFS

也許這幫助了很多更多的迭代。

var classroom = { "number": "1", "student": [{ "number": 1, "items": [{ "key": "00000000000000000000001C", "date": "2016-04-21T17:35:39.997Z" }] }, { "number": 2, "items": [{ "key": "00000000000000000000001D", "date": "2016-04-21T17:35:39.812Z" }, { "key": "00000000000000000000002N", "date": "2016-04-21T17:35:40.159Z" }, { "key": "00000000000000000000002Ñ", "date": "2016-04-21T17:35:42.619Z" }] }] }, 
 
    items = [{ "fields": { "tags": [{ "key": "00000000000000000000001C", "Batch": "50", "Bin": "01", "Tray": "02" }, { "key": "00000000000000000000002N", "Batch": "55", "Bin": "05", "Tray": "12" }, { "key": "000000000000228510000032", "Batch": "12", "Bin": "12", "Tray": "01" }], "Name": "Rubber" }, "_id": "56d19b48faa37118109977c0" }, { "fields": { "tags": [{ "key": "00000000000000000000001D", "Batch": "50", "Bin": "01", "Tray": "05" }, { "key": "00000000000000000000002Ñ", "Batch": "52", "Bin": "07", "Tray": "02" }, { "key": "221567010000000000000089", "Batch": "11", "Bin": "15", "Tray": "03" }], "Name": "Book" }, "_id": "56d19b48faa37118109977c1" }], 
 
    finalitems = []; 
 

 
classroom.student.forEach(function (student) { 
 
    student.items.forEach(function (studentItem) { 
 
     items.forEach(function (item) { 
 
      item.fields.tags.forEach(function (itemTag) { 
 
       if (itemTag.key === studentItem.key) { 
 
        finalitems.push({ 
 
         key: studentItem.key, 
 
         date: studentItem.date, 
 
         Batch: itemTag.Batch, 
 
         Bin: itemTag.Bin, 
 
         Tray: itemTag.Tray, 
 
        }); 
 
       } 
 
      }); 
 
     }); 
 
    }); 
 
}); 
 
document.write('<pre>' + JSON.stringify(finalitems, 0, 4) + '</pre>');

來源

2016-04-21 18:55:28

使用Javascript - 從另一個陣列

回答

相關問題