An example of a real-world stack is a Pez dispenser. Imagine that your virtual Pezdispenser is filled with red, yellow, and white colors and you don’t like the yellowones. Write a program that uses a stack (and maybe more than one) to remove theyellow ones without changing the order of the other candies in the dispenser.

JS-Algoritms: Stack-Exercises.js

function Stack() {
  this.dataStore = [];
  this.top = 0;
  this.clear = clear;
  this.push = push;
  this.pop = pop;
  this.peek = peek;
  this.length = length;
}

function push(element) {
  this.dataStore[this.top++] = element;
}

function peek() {
  return this.dataStore[this.top -1];
}

function pop() {
  return this.dataStore[--this.top];
}

function clear() {
  this.top = 0;
}

function length() {
  return this.top;
}

Stack.prototype.temporaryArray = [];
Stack.prototype.temporaryTop = 0;
Stack.prototype.pushInTemporaryArray = function(element) {
  this.temporaryArray[this.temporaryTop++] = element;
};

var s = new Stack();

function fullArray(element) {
  
  element.forEach(function(item, i, arr){
    s.push(item);
  });  
}

function removeAllYellow(oldColor,newColor) {
  s.dataStore.forEach(function(item, i, arr) {
    if (item == oldColor) {
      s.pushInTemporaryArray(newColor);
    } else {
      s.pushInTemporaryArray(item);
    }
  });
  s.dataStore = s.temporaryArray;
}


fullArray(["white","yellow","green","white","yellow","green","white","yellow","green"]);

removeAllYellow("yellow","red");
console.log(s.dataStore);

I am unable to understand when we have traversed array from starting in 'removeAllYellow' method then how it is a Stack.
As per my understanding stack must be read like last in first out fashion.