EcmaScript 6 and the Stack class

Let's take a moment to analyze our code and see if we can improve it using some of the new EcmaScript 6 (ES6) functionalities.

We created a Stack function that can be used as a sort of class; since JavaScript functions have constructors, we can simulate the class behavior. We declared a variable named items that is private and only accessible to the Stack function/class. However, this approach creates a copy of the variable items for each class instance created. Therefore, it does not escalate well in case we need to use several instances of the Stack class at the same time.

Let's see how we can declare the same Stack class using the new ES6 syntax and compare its pros and cons against the approach we used in this chapter.

Declaring the Stack class using ES6 syntax

The first code we will analyze is the following:

class Stack { 
  constructor () {
    this.items = []; //{1}
  } 
  push(element){ 
    this.items.push(element); 
  } 
  //other methods...