Handing touch events

tap.js

var tap = (function () {

    var isSwipe = false;
    var handlers = {};
    var eventTypes = {
        swipe: 'swipe',
        tap: 'tap'
    };

    var applyEach = function (arr, context, args) {
        var count = arr.length;
        if (!count)
            return;
        var i = 0;
        while (i < count) {
            arr[i].apply(context, args);
            i++;
        }
    };

    var trigger = function (type, e) {
        handlers[type][e.target] && applyEach(handlers[type][e.target], e.target, [e]);
        if (e.currentTarget !== e.target)
            handlers[type][e.currentTarget] && applyEach(handlers[type][e.currentTarget], e.currentTarget, [e]);
    };

    var on = function (element, type, handler) {
        if (typeof(element) === 'string')
            element = document.getElementById(element);

        if (!handlers[type])
            handlers[type] = [];

        if (!handlers[type][element])
            handlers[type][element] = [];

        handlers[type][element].push(handler);
    };

    var addListener = function (type, handler) {
        document.body.addEventListener(type, handler);
    };

    var init = function () {
        addListener('touchstart', function () {
            isSwipe = false;
        });

        addListener('touchend', function (e) {
            if (isSwipe) {
                trigger(eventTypes.swipe, e);
            } else {
                trigger(eventTypes.tap, e);
            }
            isSwipe = false;
        });

        addListener('touchmove', function (e) {
            isSwipe = true;
        });

        addListener('touchcancel', function (e) {
            isSwipe = false;
        });
    };

    init();

    return function (element) {
        return{
            on: function (type, handler) {
                on(element, type, handler);
                return this;
            }
        }
    }

})();