javascript - check if object is empty

Question

I am trying to create to javascript/jquery test to check if my object is empty and cannot figure it out.

Here is the object when it has something in it:

Answer 1

You were testing sellers which is not empty because it contains mergedSellerArray. You need to test 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 !");
}

Answer 2

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.

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,

isEmpty(mergedSellerArray); //will return true if object is not empty.

Hope this answer helped.

Answer 3

Can create the helper function :

const isEmpty = inputObject => {
  return Object.keys(inputObject).length === 0;
};

Can use it like:

let inputObject = {};
console.log(isEmpty(inputObject))  // true.

and

inputObject = {name: "xyz"}; 
console.log(isEmpty(inputObject)) // false

Answer 4

Alternatively, you can write the isEmpty function on the Object prototype.

Object.prototype.isEmpty = function() {
    for(var key in this) {
        if(this.hasOwnProperty(key))
            return false;
    }
    return true;
}

Then you can easily check if the object is empty like so.

var myObj = {
    myKey: "Some Value"
}

if(myObj.isEmpty()) {
    // Object is empty
} else {
    // Object is NOT empty (would return false in this example)
}

Source solution: https://coderwall.com/p/_g3x9q/how-to-check-if-javascript-object-is-empty

Answer 5

Here is in jQuery:

$(document).ready(function(){
	var obj={"mergedSellerArray":{}};
	alert("is empty: "+$.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/