1const person = { name: 'Nick', lastName: 'Coolguy', yearBorn: 1998 };
2
3console.log('yearBorn' in person); // expected output: true
4
5delete person.yearBorn;
6if ('yearBorn' in person === false) {
7  person.yearBorn = 2000;
8}
9
10console.log(person.yearBorn); // expected output: "2000"