Tips for golfing in D2
D is JavaScript.



Obviously not. But, when dealing  with float, double and real, nan is a value which must be handled, and, as specified by IEEE 754, NaN does not compare equal with itself.

writeln(double.nan == double.nan); // false


Meaning,

writeln(value!=value); // only true for nan


is way shorter than

import std.math;
writeln(isNaN(value));


Obviously, always use math.isNaN for real code. ;)