text: /**
   * JSON.Stringify ...
   * converts objects to string.
   * 
   * The resulting json string is called serialized.
   * 
   * No single quotes or backticks in JSON.
   * JSON does not support comments.
   */
  
  let student = {
      age: 30,
      courses: ['html', 'css'],
  };
  let json = JSON.stringify(student);
  console.log(typeof json); 
      // string
  console.log(json); 
      // {"age":30,"courses":["html","css"]}
    
  /**
   * Nested objects ...
   * are supported and converted automatically.
   */
  let meetup = {
      title: 'Conference',
      room: {
          number: 3,
          users: ['John', 'Mary']
      },
  };
  let meetup_json = JSON.stringify(meetup);
  console.log(meetup_json);
      // {"title":"Conference","room":{"number":3,"users":["John","Mary"]}}