Question

I don’t get why this.array[0] equals 1 if this.array[0] = [(2,1)]?
What does Javascript do with the 2 and how do i reach/use it? How does parenthesis work inside arrays?

I’d like to do different things with X if the boolean before it is true or false.
this.array[0] = [(true, X)] and this.array[0] = [(false, X)].

Answer 1

Parenthesis in that context act as a statement with the last item passed being the passed value.

In other words:

(2, 1) === 1

The 2 is evaluated, however, so:

(foo(), bar())

is effectively doing:

foo();
return bar();

What you want in this case is [2, 1]