Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Anyway, this is not an issue with the kata, but a problem with your code. Please use "question" label next time for similar problems.
Whatever the case, you need to return this string, not print it to console.
Wdym it's not correct? The needle is on index 5. You returned blank string.
try refreshing the page or relaunching your browser, usually it's a cache issue