Check out my other solution for even more condensed madness!

For future reference, fat arrow notation could really help make your code concise.
Example:

var ourFunction = (inputVar,inputVar2) => {return ...};
  #or...
var ourFunc = inp => whatever;
  #if you only have one input variable, you don't need the parens.
  #if you omit output braces, it will automatically return the code after =>.
  
  #Real Examples:
var add = (a,b,c) => a+b+c;

var multiply = () => {
  var args=[],out=1;
  for (var i = 0; i < arguments.length; i++){
    args.push(arguments[i]);
  };
  for (var j = 0; j < args.length; j++){
    out *= args[j];
  };
  return out;
}
  #okay, that one's really obscure. What it does is multiply together an infinite number of arguments!

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions

Yeah, I've learned a lot (level now 5kyu lmao). Going to resolve.

You should feel good! You finished a 4 kyu kata! Well done, expertise comes with time!

Because Math.floor(num) rounds num down to the nearest whole integer regardless of the decimal value.
Math.ceiling(num) does the opposite; it rounds num up if it's not a whole integer.
Math.round(num) decides whether to use floor or ceiling. Think of it as an if/else statement that rounds it up if the decimal is ≥ 0.5 and rounds it down else.