code: function get(key, defaultValue) {
          defaultValue = typeof defaultValue === "undefined" ? null : defaultValue;
          if (global.localStorage) {
              var _value = global.localStorage.getItem(key),
                  value = null;
              if (_value) {
                  try {
                      value = JSON.parse(_value);
                  } catch (e) {
                      console.error("[PreferenceManager] Failed to read preference value of key: " + key);
                  }
              } else {
                  // if not stored in localStorage, return default value from schema
                  if (_itemMap[key] && typeof _itemMap[key]['default'] !== "undefined") {
                      value = _itemMap[key]['default'];
                  } else {
                      value = defaultValue;
                  }
              }
              return value;
          } else {
              return defaultValue;
          }
      }
docs: Return value of key
  
  @param {string} key
  @param {?} defaultValue
  @return {?}