/^\d+$/
Is it essential with these? ^ $
Seems working without those two.
Anyway awesome simple, readable code than mine

Can somebody explain this /(?=[A-Z])/?

try to make it DRY

I think i made a good solution, but it keeps throwing this :(

Process was terminated. It took longer than 6000ms to complete

awesome solution

awesome solution

I think your test case has a little problem

Can you show or modify the test case after i submit the code?

suppose you have used assert method, this only shows

'Value is not what was expected'

I want to see the failed input! like this.

'Expected: "invalid11", instead got: "invalid"'