That's a good point. I chose reduce, because I preferred a declarative style for this exercise. Since the array contains only a few boxes, the performance difference is negligible. For a much larger dataset, though, I'd definitely switch to an early-exit loop. Thanks for the feedback!

Nice and clean solution, however the pageItemCount method is not correct:

p = new PaginationHelper([1,2,3,4,5,6,7,8], 4);
p.pageItemCount(1) ;   // --> this returns 0 instead of 4

Good call. I've sent a new solution with this corrected regexp:

/'?[a-z]+[a-z']*/i