Number.isFinite polyfill

Number.isFinite.js

/**
 * Number.isFinite
 * Copyright (c) 2014 marlun78
 * MIT License, https://gist.github.com/marlun78/bd0800cf5e8053ba9f83
 * 
 * Spec: http://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.isfinite
 */
if (typeof Number.isFinite !== 'function') {
    Number.isFinite = function isFinite(value) {
        // 1. If Type(number) is not Number, return false.
        if (typeof value !== 'number') {
            return false;
        }
        // 2. If number is NaN, +∞, or −∞, return false.
        if (value !== value || value === Infinity || value === -Infinity) {
            return false;
        }
        // 3. Otherwise, return true.
        return true;
    };
}