title: how can i get age from this keyword?
body: <pre><code>const meDetails = {
      firstName: 'arman',
      lastName: 'soltani',
      birthday: 1991,
      hasDriverLicense: true,
  
      calcAge: function () {
          this.age = 2037 - this.birthday;
          return this.age;
      }
  };
  
  console.log(meDetails.age);
  </code></pre>
  <p>why the age is not defined??</p>