CODE EXAMPLE FOR JAVASCRIPT

check if somethin exist in an object js

let result = targetObject.hasOwnProperty(propertyName);

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

//Example 1
let result = person.hasOwnProperty('firstName');
console.log(result); // true


//Example 2
let result = person.hasOwnProperty('age');
console.log(result); // false