At the beginning I was very confused why this counts as a solution, as it throws an error once submitting a string with only valid letters.

However the kata description at the end says "The string has a length greater or equal to one..." so I guess thats why this solution counts :P

this answer does not work for the null string - you can have to check if the value is not null

I got "TypeError: Cannot read property 'length' of null" for this.

how did this work with a length of null?

Please use spoiler flag next time.

Please use spoiler flag next time.

Can someone please explain why adding || [] can solve the null.length error. what's the raason behind it. Thanks in advance!

Technically s could also be null so I checked for both situations in my attempt

Maybe you, sir, if you excuse me, need some train on it.

Please, use spoiler flag. Your post was visible in the home page.