BookmarkInLocalStorage, step 1

gistfile1.js

(function () {
    "use strict";

    var localstorage;
    var bookmarks = [];

    function saveBookmarksToStorage() {
        localstorage["bookmarks"] = JSON.stringify(bookmarks);
    }

    function init() {
        localstorage = window.localStorage;
        if (localstorage["bookmarks"]) {
            try {
                bookmarks = JSON.parse(localstorage["bookmarks"]);
            }
            catch (err) {
                saveBookmarksToStorage();
            }
        }
    }

    var instanceMembers = {
        addNews: function (news) {
            bookmarks.push(news);
            saveBookmarksToStorage();
        },
        hasNews: function (idArticulo) {
            var result = bookmarks.filter(function (item) {
                return (item.IdArticulo == idArticulo);
            });
            return (result.length > 0);
        },
        removeNews: function (idArticulo) {
            for (var i = 0; i < bookmarks.length; i++) {
                if (bookmarks[i].IdArticulo == idArticulo) {
                    bookmarks.splice(i, 1);
                    saveBookmarksToStorage();
                    return;
                }
            }
        },
        getAllNews: function () {
            return bookmarks;
        },
    };

    var staticMembers = {};

    var BookmarkInLocalStorage = WinJS.Class.define(init, instanceMembers, staticMembers);

    // add to namespace
    WinJS.Namespace.define("Repositories",
        {
            BookmarkInLocalStorage: BookmarkInLocalStorage
        }
    );
})();