@docgunthrop, the thing is, I dont have any problems with my solution IN MY IDE. Problem appears when I upload it here.

But, to be honest, may be 'the problem' starts from understanding it. The console log says: '9 should equal 0'. This is the only one error left for my solution. What does this error exactly mean? That, if digit_root(n) func calls with n = 9, it should return 0? If it works as I expect, as I said above, I have handled this case by writing if(n==9): return 0. If this error means smth else, could you please expalain me that?

@tonylicoding, thx for advise. I will post my shitty-code here, if I dont come up with solution about this error.

I did mark it as spoiler, but I thought it wont lead to removing my comment. Anyway, @tonylicoding, may I ask you why my solution is wrong? I'd like to write ya in DM somewhere, if its possible

Omg, why this comment have been hidden?