gistfile1.js

define(function(require) {
    "use strict";

    var positions = [];
    var currentScrollPosition = 0;

    var ScrollPositions = {
        
        currentScrollPosition: function() {
            return currentScrollPosition;
        },    
        
        setRoutePosition: function(route, position) {
            positions[route] = position;
        },
        
        setCurrentScrollPosition: function(position) {
            currentScrollPosition = position;
        },
        
        setCurrentScrollPositionFrom: function(route) {
            currentScrollPosition = positions[route];
        }
        
    };

    return ScrollPositions;
});

define(function(require) {
    "use strict";
    
    var $ = require("jquery");
    var ApplicationConfig = require("modules/application/ApplicationConfig");
    require("jquery.bbq");

    var root = ApplicationConfig.applicationRoot;
    
    var URL = {

        getHashParameters: function() {
            var hashParameters = $.bbq.getState();
            return $.isEmptyObject(hashParameters) ? null : hashParameters;
        },
        
        getFragment: function() {
            return window.location.pathname.substr(root.length);
        }

    };

    return URL;
});


define(function(require) {
    "use strict";

    var routeHistory = [];
    var EventBus = require("EventBus");
    var URL = require("modules/util/URL");
    var ScrollPositions = require("modules/application/ScrollPositions");

    var currentPointer = -1;

    function getPreviousRoute() {
        return routeHistory[currentPointer - 1];
    }

    function getNextRoute() {
        return routeHistory[currentPointer + 1];
    }

    function setNextRoute(route) {
        routeHistory[currentPointer + 1] = route;
    }

    var RouteHistory = {

        saveLeaveState: function() {
            var route = URL.getFragment();

            var position = $(window).scrollTop();
            ScrollPositions.setRoutePosition(route, position);
        },

        init: function() {
            EventBus.subscribe(EventBus.LINK_CLICK_EVENT, this.saveLeaveState);
            EventBus.subscribe(EventBus.FIRE_ROUTE_EVENT, this.saveLeaveState);
        },

        reset: function() {
            routeHistory = [];
        },

        isSoftRoute: function(route) {
            return (this.isBackRoute(route) || this.isForwardRoute(route));
        },

        isBackRoute: function(route) {
            return routeHistory.length > 1 && route == getPreviousRoute();
        },

        isForwardRoute: function(route) {
            return routeHistory.length > 1 && route == getNextRoute();
        },

        atAPreviousRoute: function() {
            //pointer not at the end because it moved back from hitting back
            return currentPointer !== routeHistory.length - 1;
        },

        record: function(route) {
            if(this.isBackRoute(route)) {
                currentPointer--;
                return currentPointer;
            }

            if(this.isForwardRoute(route)) {
                currentPointer++;
                return currentPointer;
            }

            if(this.atAPreviousRoute()) {
                setNextRoute(route);
                currentPointer++;
                routeHistory = routeHistory.slice(0, currentPointer + 1);

            } else {
                routeHistory.push(route);
                currentPointer++;
            }

            return currentPointer;
        }

    };

    return RouteHistory;
});