Something something JavaScript

I guess it should be null? You are removing 1 from 1

If you fuck with types they'll fuck you.

When using the plus-sign JS parsesveverything to a String as soon as there is one to make thinks work like:
» console.log("Rants: " + 9999999);

As the minus-sign isn't available for strings the strings gets parsed to a number and could therefore crash if you take anything other than a number in a string (e.g. 1 - "abc").

JS is likes a lot to parse things. Like:
» true == 1
« true
» true === 1
« false
This is also why you should use === over == to avoid parsing when checking types.

Also did youbknow that something like:
» false || "Hello"
returns "Hello" and not true?
Once understood, it is really handy.

Weak typing at its finest