//Constructor function for Node
const Node  = function (data) {
  this.data = data;
  this.next=null;
}
//Constructor function for Stack
const Stack = function (){
  this.top=null;
  this.size= 0;
  this.min=null;
}
//Just add to prototype and all the objects inherit that behavior
Stack.prototype.push = function (data){
  //..

}
Stack.prototype.pop = function (){
 //..
}
Stack.prototype.peek = function (){
  //..
  }
Stack.prototype.isEmpty = function ()  {return this.top===null;}
Stack.prototype.minimum = function () {return this.min}

  let a  =  new Stack()
  a.push(1)
  a.push(-1)
  a.push(2)