text: /*let x=5;
  console.log(typeof x); // int type 
  let y=true;
  console.log(typeof y); // boolean type 
  let z='umair'; 
  console.log(typeof z); // string type
  */
  
  let a;
  console.log(a);
  console.log(typeof a); // undefined type 
  console.log(typeof '9');