查找和嵌套的JSON對象

Question

我用這個代碼從sJhonny's Question

數據樣本

TestObj = { 
    "Categories": [{ 
     "Products": [{ 
      "id": "a01", 
      "name": "Pine", 
      "description": "Short description of pine." 
     }, 
     { 
      "id": "a02", 
      "name": "Birch", 
      "description": "Short description of birch." 
     }, 
     { 
      "id": "a03", 
      "name": "Poplar", 
      "description": "Short description of poplar." 
     }], 
     "id": "A", 
     "title": "Cheap", 
     "description": "Short description of category A." 
    }, 
    { 
     "Product": [{ 
      "id": "b01", 
      "name": "Maple", 
      "description": "Short description of maple." 
     }, 
     { 
      "id": "b02", 
      "name": "Oak", 
      "description": "Short description of oak." 
     }, 
     { 
      "id": "b03", 
      "name": "Bamboo", 
      "description": "Short description of bamboo." 
     }], 
     "id": "B", 
     "title": "Moderate", 
     "description": "Short description of category B." 
    }] 
}; 

功能找到JSON對象所需的部分找到

function getObjects(obj, key, val) { 
    var objects = []; 
    for (var i in obj) { 
     if (!obj.hasOwnProperty(i)) continue; 
     if (typeof obj[i] == 'object') { 
      objects = objects.concat(getObjects(obj[i], key, val)); 
     } else if (i == key && obj[key] == val) { 
      objects.push(obj); 
     } 
    } 
    return objects; 
} 

使用像更新所以：

getObjects(TestObj, 'id', 'A'); // Returns an array of matching objects 

此代碼是從源代碼中選擇匹配的部分。但我想要的是用新值更新源對象並檢索更新後的源對象。

我想是這樣

getObjects(TestObj, 'id', 'A', 'B'); // Returns source with updated value. (ie id:'A' updated to id:'B' in the returned object) 

我的代碼

function getObjects(obj, key, val, newVal) { 
    var newValue = newVal; 
    var objects = []; 
    for (var i in obj) { 
     if (!obj.hasOwnProperty(i)) continue; 
     if (typeof obj[i] == 'object') { 
      objects = objects.concat(getObjects(obj[i], key, val)); 
     } else if (i == key && obj[key] == val) { 
      obj[key] = 'qwe'; 
     } 
    } 
    return obj; 
} 

這工作，如果我給obj[key] = 'qwe';，但如果我的代碼變成obj[key] = newValue;其爲未定義更新。

這是爲什麼？

Answer 1

你忘了通過NEWVALUE在嵌套調用

function getObjects(obj, key, val, newVal) { 
    var newValue = newVal; 
    var objects = []; 
    for (var i in obj) { 
     if (!obj.hasOwnProperty(i)) continue; 
     if (typeof obj[i] == 'object') { 
      objects = objects.concat(getObjects(obj[i], key, val, newValue)); 
     } else if (i == key && obj[key] == val) { 
      obj[key] = 'qwe'; 
     } 
    } 
    return obj; 
} 

Answer 2

function getObjects(obj, key, val, newVal) { 
    for (var i in obj) { 
     if (!obj.hasOwnProperty(i)) continue; 
     if (i == key && obj[key] == val) { 
      obj[key] = newVal; 
     } 
    } 
    return obj 
} 

這將做的NEWVALUE（的newval）一個發現價值的就地更新

Answer 3

這？

function update(obj, key, newVal) { 
    for(var i in obj) { 
     if(typeof obj[i] == 'object') { 
      update(obj[i], key, newVal)); 
     } else if(i === key) { 
      obj[i] = newVal; 
     } 
    } 
    return obj; 
}