How can I verify if a JavaScript object is empty?

Other Questions JavaScript
,
1

Following an AJAX call, my application might sometimes return an empty object, such as:

var a = {};

What are the ways to determine if it's indeed empty?

1 Like
2

When dealing with JavaScript objects, verifying whether an object is empty is a common challenge developers face. An empty object contains no enumerable properties, and it is crucial to identify this to avoid unnecessary data processing or logic errors in your application.

Approach to Check if an Object is Empty:

One efficient method to determine if an object is empty is by utilizing the Object.keys() method. This method returns an array of a given object’s property names. If the array’s length is zero, then the object has no enumerable properties and can be considered empty.

Code Example:

var obj = {}; // Example of an empty object.

function isObjectEmpty(obj) {
  return Object.keys(obj).length === 0;
}

console.log(isObjectEmpty(obj)); // Outputs: true

var nonEmptyObj = { key: 'value' };
console.log(isObjectEmpty(nonEmptyObj)); // Outputs: false

Explanation:

  • Object.keys(obj): This function retrieves all the keys of the object obj and places them into an array.
  • length === 0: By checking if the resulting array’s length is zero, we confirm that there are no keys in the object, indicating that it’s indeed empty.

Additional Considerations:

  • Symbols: If your objects use symbol properties, remember that Object.keys() will not include them in the returned array. To consider both symbol and string properties, you can use Reflect.ownKeys(obj).
  • Prototype Properties: This method only checks for the object’s own properties, not properties in its prototype chain. This distinction is usually beneficial, as generally, only own properties determine an object’s state.

This approach offers a clean and efficient way to determine if an object is empty, ensuring that your application logic remains error-free and optimized.