Number.sign() in javascript

Question

Wonder if there are any nontrivial ways of finding number\'s sign (signum function)?
May be shorter / faster / more elegant solutions than the obvious one

Answer 1

A solution that works on all numbers, as well as 0 and -0, as well as Infinity and -Infinity, is:

function sign( number ) {
    return 1 / number > 0 ? 1 : -1;
}

See the question "Are +0 and -0 the same?" for more information.

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Warning: None of these answers, including the now standard Math.sign will work on the case 0 vs -0. This may not be an issue for you, but in certain physics implementations it may matter.