• no random tests
• should be updated to the latest version of Node

No random tests

Testing could do with a touchup before approval.

All solution calls are run before all tests. Running tests immediately after a function call is much easier to debug.

Fixed

JS: Node v12 should be used enabled along with its appropiate assertion tools (Mocha + Chai).

JS: No random test

Added proper random tests, feel free to check them out :)

You might want to add edge cases where the property is inherited through the prototype chain. This will invalidate solutions that use in operator because it searches through the prototype chain as well.

You just have to have a bad day :-) console.log works fine and description is ok (not perfect but quite stright forward)

This is an incredibly STUPID kata! Can't see what the inputs are. Can't see what you're returning with neither return nor console.log. Errors are thrown constantly and because you can't see what you've returned you have no clue what or where to debug. Disgusting. Just disgusting.

No random tests.

Should work with falsy values

The subject of this test is not mentioned anywhere.

There are no checks for the correct format! (completely forgot about it and tests passed anyway)

Needs random tests, and please replace Test.expect with Test.assertEquals.