JavaScript – Check if an Object property is undefined
In this post we will give you information about JavaScript – Check if an Object property is undefined. Hear we will give you detail about JavaScript – Check if an Object property is undefinedAnd how to use it also give you demo for it if it is necessary.
we are going to learn how to check if an object property is undefined in JavaScript.
Consider we have the following object.
const obj = { name: "king", place: "denmark"}If we log for a property that is not defined in the above object, we will see an undefined value.
console.log(obj.age); // undefined
Using typeof operator
We can use the typeof operator to check if an object property is undefined.
The typeof operator returns the string representation of a given object property type.
if (typeof obj.age === 'undefined'){ console.log('age property is undefined');}else{ console.log('age property is not undefined');}Using in operator
Similary, we can also use the in operator to check the object property existence.
The in operator returns true if a property is present in the object, else it returns false.
const obj = { name: "king", place: "denmark"}if ('age' in obj){ console.log('age property is not undefined');} else{ console.log('age property is undefined');}Hope this code and post will helped you for implement JavaScript – Check if an Object property is undefined. if you need any help or any feedback give it in comment section or you have good idea about this post you can give it comment section. Your comment will help us for help you more and improve us. we will give you this type of more interesting post in featured also so, For more interesting post and code Keep reading our blogs