How do I test for an empty JavaScript object?

Question

After an AJAX request, sometimes my application may return an empty object, like:

var a = {}; 

How can I check whether that's the case?

Answer 1

ECMA 5+:

// because Object.keys(new Date()).length === 0; // we have to do some additional check obj // 👈 null and undefined check && Object.keys(obj).length === 0 && Object.getPrototypeOf(obj) === Object.prototype 

Note, though, that this creates an unnecessary array (the return value of keys).

Pre-ECMA 5:

function isEmpty(obj) {   for(var prop in obj) {     if(Object.prototype.hasOwnProperty.call(obj, prop)) {       return false;     }   }    return JSON.stringify(obj) === JSON.stringify({}); } 

jQuery:

jQuery.isEmptyObject({}); // true 

lodash:

_.isEmpty({}); // true 

Underscore:

_.isEmpty({}); // true 

Hoek

Hoek.deepEqual({}, {}); // true 

ExtJS

Ext.Object.isEmpty({}); // true 

AngularJS (version 1)

angular.equals({}, {}); // true 

Ramda

R.isEmpty({}); // true