cardsforscience/js/storage.js

'use strict';

/** Allows to save objects to HTML5 local storage.
 * However, it can only save properties, not functions.
 */
var ObjectStorage = (function() {
  try {
    var _s = localStorage;
    return {
      save: function(key, item) {
        _s.setItem(key, JSON.stringify(item, function (key, val) {
          if (key == '$$hashKey') {
            return undefined;
          }
          return val;
        }));
      },
      load: function(key) {
        return JSON.parse(_s.getItem(key));
      },
      clear: function() {
        _s.clear();
      }
    };
  } catch (e) {
    alert('There is no local storage for you.'
      + ' If you refresh the page, all progress will be lost');
    return {
      save: function(key, item) {},
      load: function(key) { return null; },
      clear: function() {}
    };
  };
})();