ES6 Assign Arrays from Variables

ES6 Assign Arrays from Variables
0

#1

why does it need to be [a,b]= [b,a] ;
we dont need const bc let was used?
strictmode const vs const not in strictmode?
strictmode only used inside a function?
below is first attempt:

let a = 8, b = 6;
(() => {
  "use strict";
  // change code below this line
 const [a,b]= [b,a] ;
  // change code above this line
})();
console.log(a); // should be 6
console.log(b); // should be 8