javascript - 检查对象是否为空
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javascript - check if object is empty
提问by dmikester1
I am trying to create to javascript/jquery test to check if my object is empty and cannot figure it out.
我正在尝试创建 javascript/jquery 测试以检查我的对象是否为空并且无法弄清楚。
Here is the object when it has something in it:
这是其中有东西时的对象：
{"mergedSellerArray":{"key1114":"1120"}}
And here is the object when empty:
这是空时的对象：
{"mergedSellerArray":{}}
This is the current test I have based on another SO answer but it does not work:
这是我基于另一个 SO 答案进行的当前测试，但它不起作用：
var sellers = JSON.stringify({mergedSellerArray});
if(Object.keys(sellers).length === 0 && sellers.constructor === Object) {
console.log("sellers is empty!");
}
回答by Weedoze
You were testing sellerswhich is not empty because it contains mergedSellerArray. You need to test sellers.mergedSellerArray
您正在测试sellers哪个不为空，因为它包含mergedSellerArray. 你需要测试sellers.mergedSellerArray
let sellers = {
"mergedSellerArray": {}
};
if (Object.keys(sellers.mergedSellerArray).length === 0 && sellers.mergedSellerArray.constructor === Object) {
console.log("sellers is empty!");
} else {
console.log("sellers is not empty !");
}回答by sharif2008
Here is in jQuery:
这是在 jQuery 中：
$(document).ready(function(){
var obj={"mergedSellerArray":{}};
alert("is empty: "+$.isEmptyObject(obj.mergedSellerArray));
var obj2={"mergedSellerArray":{"key1114":"1120"}};
alert("is empty: "+$.isEmptyObject(obj2.mergedSellerArray));
})<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>jsfidle: https://jsfiddle.net/nyqgbp38/
jsfiddle: https://jsfiddle.net/nyqgbp38/
回答by Vasuki Dileep
If you are using lodash library, you have an elegant way to check an empty object, array, map or a set. I presume you are aware of ES6 Import statement.
如果你使用 lodash 库，你有一种优雅的方式来检查空对象、数组、映射或集合。我想你知道 ES6 Import 语句。
import {isEmpty} from "lodash"
let obj = {};
console.log(isEmpty(obj)); //Outputs true.
let arr = [];
console.log(isEmpty(arr)); //Outputs true.
obj.name="javascript";
console.log(isEmpty(obj)); //Outputs false.
So, for your code,
所以，对于你的代码，
isEmpty(mergedSellerArray); //will return true if object is not empty.
Hope this answer helped.
希望这个答案有帮助。
回答by Ragnar
Can create the helper function :
可以创建辅助函数：
const isEmpty = inputObject => {
return Object.keys(inputObject).length === 0;
};
Can use it like:
可以像这样使用它：
let inputObject = {};
console.log(isEmpty(inputObject)) // true.
and
和
inputObject = {name: "xyz"};
console.log(isEmpty(inputObject)) // false
