JavaScript-Data-Structure | JavaScript讲解了数据结构和算法

I'm Learning data structure with javascript

and my focus now on how to implement deque?

Edite: from comments below I get useful directions on how to implement deque based array. Is there a direction how to implement deque based object using class ?

I get understand some points like I need :

• addFront()
• removeFront()
• peekFront()

• addBack()
• removeBack()
• peekBack()

but I'm confused about some points :

• how many pointers I need ? at least I know from queue I need two(head-tail) pointer but not sure if I need more in deque

• which data type in javascript convenient in this case as a base? I saw some tutors in youtube talking about circular array for example which unknown for me in JS.

edite2:

I was following a book called: learning javascript data structures and algorithms 3rd edition

in chapter5 of this book the author started to implement Deque based on object only and some variables

but I didn't understand how he did that because the code encrypted but I can still reach to his files from and test his approach github repository

I can say that @trincot answer very close of book author approach

but when I compare the results I get this [1 = author - 2 = @trincot] :

according to the book index taking about linked list comes in chapter6 so I didn't expect his solution will be based on something he didn't mentioned before

plz if I miss any point I will be grateful to tell me it ... thanks