Answers for "how to check if property is exists in javascript"

how to check wether the property exist in a object in java script

if (obj.hasOwnProperty('prop')) {
    // do something
}

check property exists

let person = {
   firstName: 'John',
   lastName: 'Doe',
   age: undefined
};

let result = person.age !== undefined;
console.log(result); // false
Code language: JavaScript (javascript)