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 hero = { name: 'Batman' }; hero.hasOwnProperty('name'); // => true hero.hasOwnProperty('realName'); // => false