Do not ask for rounding. This is documented.

No random tests

Thank you very much for your feedback! Will work on that.

Returning inconsistent datatypes is not a best practice. Either ask for null if there is no match, or ask for throwing an Error. ( The former option seems better. )

null is not an array either, but it is the best encoding of an option type ( which it does not have ) JS has.

The only info you have is that 7 years later the older sibling will be ..

".. is that in 7 years the older .."

.. the young one.

".. the younger one."

This is an automatic downvote for me; you should never have published without decent tests. But IMO the idea itself isn't that bad, just the execution.

Your kata is now unpublished, and you have the opportunity to improve it without incurring more downvotes. Make the most of that opportunity! Read the docs, read tests of kata you solved, and ask for help on Discord ( people can solve your kata even while it's unpublished if they have the link ).

It very much looks like you didn't have describe, it and require("chai") in your test suite. Please get with the times and build your test suite as documented.

You also need a lot more tests.

Needs random tests

Damn. Could you please edit this so that it couldn't be solved like this?

kata was retired

Needs more tests, and random tests

https://www.codewars.com/kata/514b92a657cdc65150000006 : "am I a joke to you?"