Am I wrong having a next solution?:

1. I assume that the first element of the given array is maximum and creating new array ('nums') with elements from 1 to that maximum number.
2. I am looping through given array and if I find any number that is greater than last maximum number, I change the value of maximum element and adding numbers from last maximum value to the new maximum value to my 'nums' array. On every loop I delete current number of the given array from 'nums' array.
   I think it is a relatively fast solution, but I can't pass all the tests, though I pass 26 tests.

Take the first letter - 'z', then 'a' on positions 4 and 5 (not indexes) and then take the last 'z'

Uhhhm, it is very strange. I've built my spyOn function exactly in this way, but I'm still getting type error, which says that callCount and wasCalledWith are not functions. Their type is undefined. I logged the body of the instance of spyOn: I get function, which has callCount and wasCalledWith methods within. Can't understand it so far

Where's the mistake?
John's katas should be: [0, 0, 1, (3-2) = 1], when Ann katas is: [1, 1, 2, 2]
Why John have made 2 katas on the day 3, if that should equals to 1?