It is not about imagination, it is about logic.
Kata says 'different type of products', it doesn't say about product count. It is about uniqueness of product.
I'm tired of such katas with wrong descriptions. So much wasted time, for nothing.

This Kata is incomplete. Wrong test cases and random tests. Why the hell 12.00.00AM should be 00.00.00 in military time? It is just wrong.

All random tests(JS) show: Expected 1. Which cannot be considered as right answer with given arrays.
Maybe this is broken?

Once again, I got this exercise solved twice (Also I got twice points because of that). Is this a bug?..

I got my kyu and identical solution for this kata duplicated.

99 bottles of beer thing is killing me TT I don't even know where is my mistake TT
suffering(

I don't get it\ Has it something to do with conctructor or what? Does it call twice method? this.number=3 => (add method)this.number=10 =>(returning)=>in the process of returning it takes this.number=10(already from add method) and calls one more time => (add.method)this.number=18 ////////Why it calls method twice? /// I fixed kata with other variable but I want to find out how to make it work initial way, if there is such way of course.

I fixed it. TY. But can you shortly explain why it works that way? Quick search didn't help.

Why is does mutate if it is just re-assignment of value which can be used just ok anytime?

Marvelous...

What an unpleasant feature. I thought every 'common' entity unlike WeakMaps-Sets copies fully by default.
Thank you.