Oh no, poisoned by OOP

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!

It's more simple to use the reverse() function of array

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.