i did this exercise but i think my knowledge by JS poor and my code is too big every time when i look another answers... i must to learn regular expressions and arrays methods for up my skills...

there is unnecessary code in this solution but let it be.
just happy I did this exercise.

ось така помилка вискакує Expected: 'null', instead got: '[NaN, NaN, NaN]' ... я вже й перевіряю всі елементи на NaN і порівнюю з довжиною головного масиву, присвоюючи null для return. де я помиляюсь?