使用 jQuery 测试 JSON 中的空数组对象
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Testing for an empty array object in JSON with jQuery
提问by mattcole
I have a request that returns a JSON object with a single property which is an array. How can I test if the array is empty?
我有一个请求，它返回一个带有单个属性的 JSON 对象，该属性是一个数组。如何测试数组是否为空？
With jQuery code like:
使用 jQuery 代码，例如：
$.getJSON(
jsonUrl,
function(data) {
if (data.RoleOwners == [ ]) {
$('<tr><td>' + noRoleOwnersText + '</td></tr>').appendTo("#roleOwnersTable tbody");
return;
}
$.each(data.RoleOwners, function(i, roleOwner) {
var tblRow =
"<tr>"
+ "<td>" + roleOwner.FirstName + "</td>"
+ "<td>" + roleOwner.LastName + "</td>"
+ "</tr>"
$(tblRow).appendTo("#roleOwnersTable tbody");
});
what can I put instead of if(data.RoleOwners == [ ]) to test if the RoleOwners is an empty array?
我可以用什么代替 if(data.RoleOwners == [ ]) 来测试 RoleOwners 是否为空数组？
Thanks, Matt
谢谢，马特
回答by svinto
(data.RoleOwners.length === 0)
回答by Sadiksha Gautam
You can also do jQuery.isEmptyObject(data.RoleOwners)
你也可以这样做 jQuery.isEmptyObject(data.RoleOwners)
回答by Arun Pratap Singh
below code works perfectly fine no need to write one of yours own.
下面的代码工作得很好，不需要自己写一个。
// anyObjectIncludingJSON i tried for JSON object.
if(jQuery.isEmptyObject(anyObjectIncludingJSON))
{
return;
}
回答by Sameera Prasad Jayasinghe
Check this
检查这个
JSON.parse(data).length > 0
回答by John Middlemas
An array (being an object too) can have non numeric properties which are not picked up by testing for zero length. You need to iterate through the properties just like testing for an empty object. If there are no properites then the array is empty.
数组（也是一个对象）可以具有非数字属性，这些属性不会通过测试零长度来获取。您需要遍历属性，就像测试空对象一样。如果没有属性，则数组为空。
function isEmptyObject(obj) {
// This works for arrays too.
for(var name in obj) {
return false
}
return true
}
