That because the pattern is strongly checking for only digit (0 - 9) nothing else

Same. This is by no means a 6kyu skill level challenge. The base solution here is a core fundamental javascript concept.

my code outputs that everything is correct except for empty arrays, like this error: last( [] ) == null - Expected: null, instead got: undefined.
what's wrong with it?

voted as "somewhat" for being at 8-kyu-level.

Happened to me in another kata, but I remember to add 'initialvalue' since then. Haha!

I've started from filter, but the test found it incorrect, and then I tried many methods, including endsWith, for loop, map, when I re-read the task and found out that it was saying to output even numbers, when I was trying to output odd ones. What a waste of time by me

I imagine putting this code on a simple calculator.

The first three parentheses are lookaheads to determine whether the given string contains a lowercase letter, an uppercase one and a digit. Then the "main" part goes, which target is to match only strings of size 6 or more containing only appropriate symbols.

P.S. The first three parentheses are not enough to solve the task, since the string aA1# can match, which is obviously is not needed.

I solved the kata with while loop, but have exactly no idea what's going on here.

cool kata!

thank you for the explanation bro! it's very necessary for gods of js like me :D

Thanks, good kata!

Coding is a good job if you love it or just got interested in it. If you see no meaning in it, find another job, but if you see some, learn it step-by-step. It's like any other job will start rewarding you, but unlike the others, it'll do it exponentially. Like "the more you give, the more you get**2"