Draw Items from One JavaScript Array to Another using a Pair ADT

We want to be able to pick nine random cards from an array of twelve cards, but can run into problems of keeping both the cards already draw and the cards left to draw from. Tracking two bits of state like this can create some hard to maintain argument gymnastics when creating our functions. Luckily we have a datatype Pair at our disposal that allows us to combine two values in to one value.

We will use this Pair type to model both a draw pile and a remaining pile, and take advantage of a couple special properties of Pair that will allow us to combine two Pair instances in a meaningful way by chaining. Just like we have done time and time again with the State ADT