Single Die Roll Counter Wrap Around Nested Ternary Conditional
Found the answer: 

it's correct expcet 'D6 needs to be D6. :)
D6 because i defined it above my module. I just used an apostrophe which it is not. 

Besides, how does this all work? 
Well ternary conditionals work as so:  variable = conditional ? true : false; 

so next = count if my in is false. 

Now what I have here is when it is true there is a nested ternary conditional: 

''(count == `D6) ? 'D1 : (count + 1)``

so if count is equal to my D6 (my die has a value of 6) then I need it to wrap around toD1 (die of value 1), because the die here can't have value 7, 8, 9, etc. We want the counting to wrap back around. 

Therefore, 

when in is true and count is not D6 then I count up.
when  ``in`` is true and ``count`` isD6  then I make next equal to `D1 
when in is false then next is just equal to count, meaning it stays current and no "roll" is recorded. 

Hope that all makes sense!