Less Than or Equal to Not Less Than or Equal to
It turns out, despite not being less than zero, or equal to zero, null is indeed less than or equal to zero:
> null < 0
false
> null == 0
false
> null <= 0
true
This means the expressions a < b || a == b
and a <= b
do not always yield the same result.
It turns out the same is true for the greater than comparison too, so at least it's consistent, I guess...