1if (obj.hasOwnProperty('prop')) {
2    // do something
3}

1const object1 = new Object();
2object1.property1 = 42;
3
4console.log(object1.hasOwnProperty('property1'));
5// expected output: true

1for (var name in object) {  
2    if (object.hasOwnProperty(name)) { 
3        // do something with name                    
4    }  
5}
6
7// OR
8
9const hero = {
10  name: 'Batman'
11};
12
13hero.hasOwnProperty('name');     // => true
14hero.hasOwnProperty('realName'); // => false

1const hero = {
2  name: 'Batman'
3};
4
5hero.hasOwnProperty('name');     // => true
6hero.hasOwnProperty('realName'); // => false

1var person = {'first_name': 'bill','age':20};
2
3if ( person.hasOwnProperty('first_name') ) {
4    //person has a first_name property
5}
6