DOM.js

(function(window, document) {
    'use strict';
    function DOM(element) {
        this.element = document.querySelectorAll(element);
    }

    DOM.prototype.on = function on(event, callback) {
        Array.prototype.forEach.call(this.element, function(element) {
            element.addEventListener(event, callback, false);
        });
    };

    DOM.prototype.off = function off(event, callback) {
        Array.prototype.forEach.call(this.element, function(element) {
            element.removeEventListener(event, callback, false);
        });
    };

    DOM.prototype.get = function get() {
        if (this.element.length === 1)
            return this.element[0];
        
        return this.element;
    };

    DOM.prototype.forEach = function forEach() {
        Array.prototype.forEach.apply(this.element, arguments);
    };

    DOM.prototype.map = function map() {
        Array.prototype.map.apply(this.element, arguments);
    };

    DOM.prototype.filter = function filter() {
        Array.prototype.filter.apply(this.element, arguments);
    };

    DOM.prototype.reduce = function reduce() {
        Array.prototype.reduce.apply(this.element, arguments);
    };

    DOM.prototype.reduceRight = function reduceRight() {
        Array.prototype.reduceRight.apply(this.element, arguments);
    };

    DOM.prototype.every = function every() {
        Array.prototype.every.apply(this.element, arguments);
    };

    DOM.prototype.some = function some() {
        Array.prototype.some.apply(this.element, arguments);
    };

    DOM.isArray = function isArray(arr) {
        return Object.prototype.toString.call(arr) === '[object Array]';
    };

    DOM.isObject = function isObject(obj) {
        return Object.prototype.toString.call(obj) === '[object Object]';
    };

    DOM.isFunction = function isFunction(func) {
        return Object.prototype.toString.call(func) === '[object Function]';
    };

    DOM.isNumber = function isNumber(number) {
        return Object.prototype.toString.call(number) === '[object Number]';
    };

    DOM.isString = function isString(str) {
        return Object.prototype.toString.call(str) === '[object String]';
    };

    DOM.isBoolean = function isBoolean(boolean) {
        return Object.prototype.toString.call(boolean) === '[object Boolean]';
    };

    DOM.isNull = function isNull(nullValue) {
        return Object.prototype.toString.call(nullValue) === '[object Null]' ||
            Object.prototype.toString.call(nullValue) === '[object Undefined]';
    };

    window.DOM = DOM;
})(window, document);