stack.js

class Stack {
    constructor(){
        this.data = [];
        this.top = 0;
    }
    push(element) {
      this.data[this.top] = element;
      this.top = this.top + 1;
    }
   length() {
      return this.top;
   }
   peek() {
      return this.data[this.top-1];
   }
   isEmpty() {
     return this.top === 0;
   }
   pop() {
    if( this.isEmpty() === false ) {
       this.top = this.top -1;
       return this.data.pop(); // removes the last element
     }
   }
   print() {
      var top = this.top - 1; // because top points to index where new    element to be inserted
      while(top >= 0) { // print upto 0th index
          console.log(this.data[top]);
           top--;
       }
    }
    reverse() {
       this._reverse(this.top - 1 );
    }
    _reverse(index) {
       if(index != 0) {
          this._reverse(index-1);
       }
       console.log(this.data[index]);
    }
}