function sayHello() {
  console.log(this.name, this.age);
}

const person = {
  name: 'Alice',
  age: 30,
  sayHello: sayHello,
  spouse: {
    age: 32,
    sayHello: sayHello
  }
};

person.sayHello(); // Alice, 30
person.spouse.sayHello(); // undefined, 32
sayHello(); // undefined, undefined