Dickson storage

dickson-storage.js

(function() {
  var ds = window.dicksonStorage = { };

  var data = getData();

  var INTERVAL = 400;
  setInterval(ianWorker, INTERVAL);

  ds.clear = clear;
  function clear() {
    data = {};
    setData();
  }

  ds.getItem = getItem;
  function getItem(key) {
    return data[key] === undefined ? null : data[key];
  }

  ds.setItem = setItem;
  function setItem(key, value) {
    data[key] = value;
    setData();
  }

  ds.removeItem = removeItem;
  function removeItem(key) {
    delete data[key];
    setData();
  }

  function getData() {
    return JSON.parse(localStorage.dicksonStorage || '{}');
  }

  function setData() {
    localStorage.dicksonStorage = JSON.stringify(data);
  }

  function ianWorker() {
    if (Date.now() - localStorage.dicksonTicket > INTERVAL * 2)
      clear();

    localStorage.dicksonTicket = Date.now();
  }
})();