For example, how exactly does the regular expression test truthy for the smiley ";)"?

Nice and clean solution! I'm only slightly familiar with regular expressions, but I am trying to improve my understanding of it. Would you mind explaining the "?" between the valid noses and the valid mouths in your variable titled smileyRegExp? I've seen others describe it as a lookahead, but its purpose and effect are still a bit unclear to me. Thank you for your time ^.^

I don't think 3.14159 is either an even number or an odd number, since it's not even an integer.

not an issue.

Your suggestion is accepted and included in this kata.

Your wording is fine! I should have done a better job of reading.

However, an example would have actually cleared it right up for me (and I was actually disappointed there wasn't one to reference).

For example:

const ted = new Bouncer({ minAge: 18, guestList: ["Lo", "Mc"] })

ted.letIn([
    { name: "Joe", age: 6 },
    { name: "Lo", age: 3 },
    { name: "Hugh", age: 33 }
])

returns: [ { name: 'Lo', age: 3 }, { name: 'Hugh', age: 33 } ]

Sorry but I don't understand what you mean. Lo should get it, since she is on guest list.
Age should be equal or above bouncers's age limit or *name should be on guest list to enter the club*.
Can you suggest message that would be easier to understand please?

@Lazy Cat - Each kata has a discussion area, and you should post your questions and comments directly to that discusison area. In addition, since you're showing code, you should mark your comment as a "Spoiler" so that you aren't showing that code to other people who are also trying to train on that kata.

The discussion area for the kata you're having issues with is https://www.codewars.com/kata/583203e6eb35d7980400002a/discuss/php

@AcesOfGlory - Thank you. It's always the little things that trip me up the worst. :-(

Something is definitely schizophrenic!

The problem is that each of those was a working solution for a previous version of the kata. Another user ran into a problem trying to solve the kata, and in trying to figure out if their problem was because of my tests, all the previous solutions suddenly become "Invalid Solutions" HOWEVER THEY ALL VALIDATE (i.e. pass all the tests) within the Kata editor! (It's "schizophrenic" enough that I even pinged Voile (who previously helped) in the gitter channel asking for help - https://gitter.im/Codewars/codewars.com/kata-authoring-help?at=596cf78689aea4761da984d5 )

edited to add: It looks like JohanWiltink's solution eventually passed, but OverZealous' and Voile's solutions, WHICH PASS in the Kata Editor are still being marked as "Invalid Solutions" here. >:(

So, YOU "validate" (in your comments) what YOUR kata revision has invalidated ?
May be you should tag it "schizophrenic"...

; ) )

You need to throw the error, not return it.

Please provide more information on the expected error for an empty array.