How to Test For an Empty Object in JavaScript

Topic: JavaScript / jQueryPrev|Next

Answer: Use the Object.keys() Method

You can simply use the Object.keys() method along with the typeof operator to test for an empty JavaScript object (contains no enumerable properties). Also, since null == undefined is true,
obj != null will catch both null and undefined values.

The isEmptyObject() function in the following example will check if an object is empty. However, it will only test plain objects (created using "{}" or "new Object()").

// Defining a function
function isEmptyObject(obj) {
    if(typeof obj === 'object' && obj != null && Object.keys(obj).length !== 0){
        return false;
    } else {
        return true;
    }
}

// Testing few values    
console.log(isEmptyObject({})); // Prints: true
console.log(isEmptyObject({name: "Harry", age: 18})); // Prints: false
console.log(isEmptyObject(null)); // Prints: true
console.log(isEmptyObject(undefined)); // Prints: true

If you're using jQuery you can simply use the jQuery.isEmptyObject() method to check if an object is empty. Let's try out an example to understand how it basically works:

// Testing few values    
console.log(jQuery.isEmptyObject({})); // Prints: true
console.log(jQuery.isEmptyObject({name: "Harry", age: 18})); // Prints: false
console.log(jQuery.isEmptyObject(null)); // Prints: true
console.log(jQuery.isEmptyObject(undefined)); // Prints: true

See the tutorial on JavaScript Objects to learn more about creating and manipulating objects.

Related FAQ

Here are some more FAQ related to this topic:

• How to check if a key exists in a JavaScript object
• How to check if an object property is undefined in JavaScript
• How to get the length of a JavaScript object