es5-ext/number/is-number.js

ECMAScript extensions and shims

"use strict";

var objToString = Object.prototype.toString, id = objToString.call(1);

module.exports = function (value) {
	return (
		typeof value === "number" ||
		value instanceof Number ||
		(typeof value === "object" && objToString.call(value) === id)
	);
};