Creating a queue

We are going to create our own class to represent a queue. Let's start from the basics and declare our class:

function Queue() {
    //properties and methods go here
}

First, we need a data structure that will store the elements of the queue. We can use an array to do it, just like we used for the Stack class in the previous chapter (you will notice the Queue and Stack class are very similar, just the principles for adding and removing the elements are different):

var items = [];

Next, we need to declare the methods available for a queue:

• enqueue(element(s)): This adds a new item (or several items) at the back of the queue.
• dequeue(): This removes the first item from the queue (the item that is in the front of the queue). It also returns the removed element.
• front(): This returns the first element from the queue, the first one added, and the first one that will be removed from the queue. The queue is not modified (it does not remove the element; it only returns the element...