# How to check if an object is empty in JavaScript

By Atta Ur Rehman Shah (https://attacomsian.com/about). Published Aug 18, 2019, updated Sep 19, 2022. Topics: JavaScript.
Canonical URL: https://attacomsian.com/blog/check-if-javascript-object-is-empty

> Learn how to use the Object.entries(), Object.keys(), and Object.getOwnPropertyNames() methods to check if an object is empty in JavaScript.

For JavaScript [objects](https://attacomsian.com/blog/objects-prototypes-classes-javascript#objects), there is no built-in `.length` or `.isEmpty` method available to check if they are empty. 

Here are 4 different methods that you can use to make sure that a given object does not have its own properties:

## `Object.entries()` Method

The [`Object.entries()`](https://attacomsian.com/blog/object-entries-values-javascript#objectentries-method) method takes an object as an argument and returns an array of its enumerable property `[key, value]` pairs. 

We can then use the `.length` property of the [array](https://attacomsian.com/blog/javascript-arrays) to check if it contains any item:

```javascript
const user = {}

Object.entries(user).length === 0 // true

const bird = {
  name: 'Penguin',
  avatar: '?'
}

Object.entries(bird).length === 0 // false
```

> **Note:** `Object.entries()` only works in [modern browsers](https://caniuse.com/#search=object.entries()) and is not supported by IE. If you need backward compatibility, consider adding a [polyfill](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries#Polyfill) or use `Oject.keys()` method instead.

## `Object.keys()` Method

The `Object.keys()` method is the best way to check if an object is empty because it is supported by almost all browsers, including IE9+. 

It returns an array of a given object's own property names. So we can simply check the length of the array afterward:

```javascript
Object.keys({}).length === 0 // true

Object.keys({ name: 'Atta' }).length === 0 // false
```

## `Object.getOwnPropertyNames()` Method

The [`Object.getOwnPropertyNames()`](https://attacomsian.com/blog/javascript-object-get-all-own-properties) method takes an object as parameter and returns an array of its own property names:

```javascript
Object.getOwnPropertyNames({}).length === 0 // true

Object.getOwnPropertyNames({ id: 1, name: 'John Doe' }).length === 0 // false
```

## 3rd-Party Libraries

If you are already using 3rd-party libraries like jQuery or Lodash in your web application, you can also use them to check if an object is empty:

```javascript
// jQuery
jQuery.isEmptyObject({}) // true

jQuery.isEmptyObject({ id: 1, name: 'John Doe' }) // false

// Lodash
_.isEmpty({}) // true

_.isEmpty({ name: 'Emma' }) // false
```

## Prototype Function

You can write a helper function `isEmpty()` and add it to the object's [prototype](https://attacomsian.com/blog/objects-prototypes-classes-javascript#prototypes):

```javascript
Object.prototype.isEmpty = function () {
  return Object.keys(this).length == 0
}
```

Now you can call the `isEmpty()` method on any JavaScript object to check if it has its own properties:

```javascript
const obj = {}

obj.isEmpty() // true

const site = {
  title: 'Twitter',
  website: 'https://twitter.com'
}

site.isEmpty() // false
```

Be careful while extending the `Object` prototype, as it can cause issues when used together with other JavaScript frameworks. Instead, use the `Object.keys()` method in JavaScript applications to check if an object is empty.