[Math Check] Only want valid directions: 0, 45, 90, 135, 180, 225, 270, 315 or back to 0

UL UP UR LT ** RT DL DN DR Moving on a grid in the directions shown above in text (token is at **) Looking to have only 0, 45, 90, 135, 180, 225, 270, 315 or back to 0. Passing the token rotation (angle) that might be -32.222 or 634.333 (or whatever.) fixAngle = function(angle) { angle = angle % 360; angle = (angle + 360) % 360; angle = Math.round(angle / 45) * 45; angle = Math.round(angle); if(360 === angle){ angle = 0;} return angle; }, I have read Javascript: The Good Parts... and even talked to Douglas Crockford on Skype. He says this is good, just wondering if I have this correct.

Are you trolling me? =D I'd probably write it like this: var fixAngle = function(angle){ return (Math.round(angle/45)*45)%360 + (angle<0 ? 360 : 0); }; Your first two lines are dealing with getting a positive angle between 0 and 359, delaying that until later makes it fewer operations. I think that second Math.round() is redundant, as the first will return an integer and multiplying by another integer shouldn't introduce rounding errors... In mine, the modulus will cause the term before the + to be in the range between -315 and +315. The term to the right of the + then performs the range fix up if the result is <0. (Interesting note: the first term can result in -0, but that's still not < 0, so it's good! =D ) > _.map([-8000, -32.222, 0, 48, 359, 634.333, 8000],fixAngle); [270, 315, 0, 45, 0, 270, 90] Cheers!

Thanks! It felt a little long winded in the code. That could be a handly little thing. I have seen some funny decimals with obj.top and obj.left and I really didn't feel like getting bit with funny decimals from obj.rotation.

Yeah, I have a simpler version of this in my TokenMod script, but it only bothers to keep the range in (-360, 360). (which is to say, it just mods by 360. =D)