Creating the Deque class

As usual, we will start by declaring the Deque class located in the file src/05-queue-deque/deque.js:

class Deque {
  #items = [];
}

We will continue using an array-based implementation for our data structure. And given the deque data structure allows inserting and removing from both ends, we will have the following methods:

• addFront(item): This method adds a new element at the front of the deque.
• addRear(item): This method adds a new element at the back of the deque.
• removeFront(): This method removes the first element from the deque.
• removeRear(): This method removes the last element from the deque.
• peekFront(): This method returns the first element from the deque.
• peekRear(): This method returns the last element from the deque.

The Deque class also implements the isEmpty, clear, size, and toString methods (you can check the complete source code by downloading the source code bundle for this book). The code for these is the same as for the Queue class.

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