How to Check If an Object Property is Undefined in JavaScript

  672 views   1 year ago Javascript

Use the strict equality operator (===)

You can use the typeof operator in combination with the strict equality operator (===) to check or detect if a JavaScript object property is undefined.

Let's take a look at the following example to understand how it actually works:

<script>
    var person = {
        name: "Clark",
        age: 32,
        country: "United States"
    };
    
    // Access an existing object property
    console.log(person.age); // Prints: 32
    
    // Detect if object property is undefined
    if(typeof person.gender === "undefined"){
        console.log("This property is not defined.");
    }
</script>

 

Author : Harsukh Makwana
Harsukh Makwana

Hi, My name is Harsukh Makwana. i have been work with many programming language like php, python, javascript, node, react, anguler, etc.. since last 5 year. if you have any issue or want me hire then contact me on [email protected]

Related Articles