You were right - Javascript lacks a modulo operator. Javascript does have a `%` operator, and in many languages that performs the modulo operation ... but in JS it actually calculates the remainder. This is confusing because in some situations remainder and modulo look similar, but they're not. So if we compare JS and Python (where `%` means "modulo") ...

    $ python3
    Python 3.7.3 (default, Jul 25 2020, 13:03:44) 
    [GCC 8.3.0] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>> 10 % 3
    1
    >>> 10 % -3
    -2
    >>> 
    $ node
    > 10 % 3
    1
    > 10 % -3
    1

In the case we're talking about - is_odd - I don't think it matters, but there is a difference and it could cause some surprises if you're not prepared.

edit: I called this operation "remainder" ... but you don't exactly say "10 remainder 3" for this operation. I don't know what to call it, "divide-by-and-return-absolute-of-whats-left" is not very catchy