A percent is a not a unit of measure

[mjschlot]

Version 2.0.0 included a breaking change that makes sense but has an error. That change was:

• reduce-css-calc will now throw when trying to multiply or divide by the same unit (e.g. calc(200px * 20px)), and also when trying to divide by zero.

While a unit like "px" times "px" should throw an error, a percent ("%") is not a unit; it denotes a fraction of 100. It is legitimate to multiple 50% by 50%, as it is the exact same mathematical meaning as 50/100 * 50/100.

I may be wrong here, but I'm pretty sure. Thoughts?

[mjschlot]

Well shoot. Maybe it isn't that simple ... Because this is CSS math; not "standard" math.

I'm having a hard time thinking of an example where it would be unsafe to treat a percent as traditional math and drop it as a "unit" if there is another unit within a formula. But perhaps it is not as clear cut as I first thought.

I am going to close this issue for now since I am now less certain a change should be made.