Wednesday, October 21, 2015

Bleeding Edge JavaScript Math

In today's comic, Science Frog finds himself on the bleeding edge by accident - literally. Just so I have a nice tie-in with that, I'm going to share some bleeding edge JavaScript math functions. Not literally. You won't actually bleed. Unless you cut yourself on your keyboard, in which case you really should get a better keyboard.

Why do I say this is bleeding edge? I guess I could say cutting edge or leading edge. I could also just drop the idioms and say that these are new language features. The first is only available in the Firefox nightly builds at the moment. How's that for the edge of some kind?!

What is that new feature? An exponentiation operator! That's right, no more need for Math.pow()! Just use double asterisks. This is a feature currently planned for ECMAScript 7 next year, but you can try it in a Firefox nightly build today (it may be included in next month's standard release):

var e = 2 ** 8;
var p = Math.pow(2, 8);

console.log(e === p);  // prints true

Not exciting enough for you? Come on, Java doesn't even have an exponentiation operator and it's been a legitimate language for at least 10 years! I guess Python does, but now all you Python devs don't have an excuse for not switching to JavaScript.

Now for something slightly less edgy. Since Math.pow() will become obsolete, I guess it's only fair that it get a new function. Added as part of ECMAScript 6 this year, Math.fround() is that function. Given a number, it returns the nearest single-precision floating point number. What? Try this (it works in standard Firefox releases since 26 and Chrome since 38):

var x = Math.fround(2.567);
console.log(x); // prints 2.566999912261963

var y = Math.fround(3);
console.log(y); // prints 3

var z = Math.fround(3.3);
console.log(z); // prints 3.299999952316284

I'm sure it makes sense now - Math.fround() gives you the most precise floating point equivalent of a number.

That's all I have to share today. I'm actually away from home this week - in the Dallas area for some software architecture training. But I did all the comics for this week before I left, so no problems there! Missing the comics is fround upon. Sorry, couldn't resist that one. comic for 21 October 2015

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