const hero = {

  name: 'Batman'

};

​

hero.hasOwnProperty('name');     // => true

hero.hasOwnProperty('realName'); // => false

if (obj.hasOwnProperty('prop')) {

    // do something

}

var person = {'first_name': 'bill','age':20};

​

if ( person.hasOwnProperty('first_name') ) {

    //person has a first_name property

}

​

myObj.hasOwnProperty(myProp)

const userOne = {

  name: 'Chris Bongers',

  email: 'info@daily-dev-tips.com',

};

​

const userTwo = {

  name: 'John Do',

};

​

console.log(userOne.hasOwnProperty('email'));

// Returns: true

​

console.log(userTwo.hasOwnProperty('email'));

// Returns: false

let result = person.hasOwnProperty('firstName');

console.log(result); // true

Code language: JavaScript (javascript)

if (typeof receviedData?.d?.heartbeat_interval != "undefined") {

}

​

// OR 

​

if (receviedData?.d?.heartbeat_interval !== undefined) {

​

}

// the coolest way

const obj = {

 weather: 'Sunny; 

}

​

if('weather' in obj) {

 // do something 

}

​

​

let person = {

   firstName: 'John',

   lastName: 'Doe',

   age: undefined

};

​

let result = person.age !== undefined;

console.log(result); // false

Code language: JavaScript (javascript)

const employee = {

    id: 1,

    name: "Jhon",

    salary: 5000

};

​

const isSalaryExist = "salary" in employee;

console.log(isSalaryExist); //true

​

const isGenderExist = "gender" in employee;

console.log(isGenderExist); //false