1  'use strict';
 2  
 3  var $isNaN = require('./isNaN');
 4  
 5  /** @type {import('./sign')} */
 6  module.exports = function sign(number) {
 7  	if ($isNaN(number) || number === 0) {
 8  		return number;
 9  	}
10  	return number < 0 ? -1 : +1;
11  };