如何使用JavaScript過濾複雜的json對象？

Question

我有以下的JSON對象：

var json = { 
    "Lofts": "none", 
    "Maisons": "2", 
    "HOMES": [{ 
     "home_id": "1", 
     "price": "925", 
     "num_of_beds": "2" 
    }, { 
     "home_id": "2", 
     "price": "1425", 
     "num_of_beds": "4", 
    }, { 
     "home_id": "3", 
     "price": "333", 
     "num_of_beds": "5", 
    }] 
}; 

如何過濾此對象，並保持與家物產其中HOME_ID = 2？

結果：

var json = { 
    "Lofts": "none", 
    "Maisons": "2", 
    "HOMES": [{ 
     "home_id": "2", 
     "price": "1425", 
     "num_of_beds": "4", 
    }] 
}; 

有沒有什麼辦法可以循環對象和mantein所有屬性（也閣樓和MAISONS）？

感謝

Answer 1

您可以使用Array#filter，並將結果直接分配給屬性HOMES。

var json = { "Lofts": "none", "Maisons": "2", "HOMES": [{ "home_id": "1", "price": "925", "num_of_beds": "2" }, { "home_id": "2", "price": "1425", "num_of_beds": "4", }, { "home_id": "3", "price": "333", "num_of_beds": "5", }] }; 
 

 
json.HOMES = json.HOMES.filter(function (a) { 
 
    return a.home_id === '2'; 
 
}); 
 

 
document.write('<pre>' + JSON.stringify(json, 0, 4) + '</pre>');

Answer 2

通過使用工具庫Lodash，你可以使用的方法find如果home_id是獨一無二的。

查找：迭代過的collection（陣列|對象）元素，它返回第一元件predicate返回truthy對。謂詞用三個參數調用：（value，index | key，collection）。

_.find(collection, [predicate=_.identity]) 

代碼：

var json = {"Lofts": "none","Maisons": "2","HOMES": [{"home_id": "1","price": "925","num_of_beds": "2"}, {"home_id": "2","price": "1425","num_of_beds": "4"}, {"home_id": "3","price": "333","num_of_beds": "5"}]}; 
 
json.HOMES = [_.find(json.HOMES, {home_id: '2'})]; 
 

 
document.write('<pre>' + JSON.stringify(json, 0, 4) + '</pre>');

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.12.0/lodash.min.js"></script>

如果有多個對象具有相同home_id你應該做一個filter：

_.filter(collection, [predicate=_.identity])

Filter：遍歷collection（Array | Object）的元素，返回所有元素謂詞的數組返回truthy。謂詞用三個參數調用：（value，index | key，collection）。

代碼：

var json = {"Lofts": "none","Maisons": "2","HOMES": [{"home_id": "1","price": "925","num_of_beds": "2"}, {"home_id": "2","price": "1425","num_of_beds": "4"}, {"home_id": "3","price": "333","num_of_beds": "5"}]}; 
 
json.HOMES = _.filter(json.HOMES, {home_id: '2'}); 
 

 
document.write('<pre>' + JSON.stringify(json, 0, 4) + '</pre>');

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.12.0/lodash.min.js"></script>