Why is Math.pow(-0, -7) === -Infinity?

Question

Is there a rationale for Math.pow(-0, x) evaluating to Infinity for all negative x, except for the odd ones when it's -Infinity? I mean:

Math.pow(-0, -6);          // Infinity
Math.pow(-0, -7);          // -Infinity
Math.pow(-0, -7.33);       // Infinity
Math.pow(-0, -Infinity);   // Infinity

Fiddle

I'm aware that a positive odd power of a negative number is negative, but this is clearly not the case here: -7 is not a positive exponent, and while -0 is indeed a number if you open your mind, it's not a negative one.

This behaviour makes mathematically no sense, and I don't see a practical use or technical convenience for it either, so I suspect the specification must rely on historical/compatibility reasons. Any insights?

Answer 1

I believe this is for consistency with powers of other negative numbers. When you raise a negative number to an even power, you always get a positive result. But when you raise a negative number to an odd power, you get a negative result. Raising zero to a negative power always results in infinity (because it's equivalent to dividing by zero); in the case of negative zero, the sign alternates just like other negative numbers.