EasterEgg.js

;(function easterEgg ($, namespace) {
    function EasterEgg (options) {

        var defaults = {
            timeout : 2000,     // Time you have to enter a new key before the keysPressed array gets flushed
            logKeys : false,    // Console log the keys that you are pressing.  Helps to determine combos.
            combos  : []        // [[keys], callback] - Add the combos from the start here.  OR, add them with a returned function after the fact
        };

        var settings = $.extend({}, defaults, options);

        var $document = $(document),

            easterTimeout,              // Placeholder for easterEgg timeout
            eventNamespace,             // Unique namespace so that keypressing can be unbound
            keysPressed = [],           // Dynamically populates with key codes as they are actively pressed
            combos = settings.combos;   // [[keys], callback]

        // Private Functions
        ////////////////////

        function addPressedKey (e) {
            /**
             *  Populates keysPressed array with the event's key code and start a timeout,
             *  Then call matchKeysPressed.
             *
             */

            var keycode = e.keyCode;
            keysPressed.push(keycode);
            clearTimeout(easterTimeout);
            easterTimeout = setTimeout(removePressedKey, settings.timeout);
            matchKeysPressed();

            // Just log the keys pressed.
            if (settings.logKeys) {
                console.log('=======================');
                console.log('key pressed: ' + keycode);
                console.log('current keys: ' + keysPressed);
            }
        }

        function removePressedKey () {
            /**
             * Reset the keysPressed Array
             */
            keysPressed = [];
        }

        function matchKeysPressed () {
            /**
             *  If key combinations have been added to the combos array, loop through the combinations.
             *  Within each combination, check the keysPressed array for the keys needed to be active for the callback to execute.
             *  If a key isn't found in keysPressed array, turn the doCallback switch to false and do not perform the callback.
             *  If all the keys exist, do the callback
             */

            if (combos.length) {
                for (var i in combos) {
                    var thisCombo = combos[i];
                    var thisKeys = thisCombo[0];
                    var thisCallback = thisCombo[1];
                    var doCallback = true;
                    if (thisKeys.length) {
                        for (var i in thisKeys) {
                            var key = thisKeys[i];
                            if (keysPressed[i] !== key) {
                                doCallback = false;
                                break;
                            }
                        }
                    }
                    if (doCallback) {
                        thisCallback();
                    }
                }
            }
        }

        function initialize () {
            /**
             *  Create a random eventNamespace ID that will be unique to this instance of key events.
             *  Unique namespaces allow the document to be unbound from key presses relative to this instance
             *  Bind events to document with unique namespace
             */

            eventNamespace = '.keycombo_' + Math.ceil(Math.random()*100);
            $document
                .on('keydown' + eventNamespace, function (e) {
                    addPressedKey(e);
                });
        }

        // Private Functions
        ////////////////////

        function getCombos () {
            /**
             *  As a developer, if you need to retrieve a list of active key combinations, call this function.
             *  Returns - combos array.
             */
            return combos;
        }

        function addCondition (keys, callback) {
            /**
             *  Populates the combos array with an array containing [keys, callback]
             *  note: keys needs to be an array.
             */
            combos.push([keys, callback]);
        }

        function unbindKeypress () {
            /**
             *  Unbinds keydown and keyup from document
             */
            $document.off('keydown' + eventNamespace).off('keyup' + eventNamespace);
        }


        // Initialize
        /////////////
        initialize();

        return {
            combos  : getCombos,
            add     : addCondition,
            unbind  : unbindKeypress
        };
    }

    namespace.easter = EasterEgg;
})(window.jQuery, window.project || {});