Reverse String

 function reverse(str){
   let stack = [];

   // push letter into stack

   for(var i=0; i<str.length; i++){
        stack.push(str[i]);
   }
 
   // pop letter from the stack

   let revers_string = '';
   while(stack.length > 0){
           revers_string += stack.pop();
   }

   return reverseStr;

}
console.log(reverse('JavaScript Stack')); //kcatS tpircSavaJ