Extend the localStorageService for Angular (https://github.com/grevory/angular-local-storage) with the possibility of expiring entries.

localStorageService.expire.js

/**
 * extend the localStorageService (https://github.com/grevory/angular-local-storage)
 * 
 * - now its possible that data stored in localStorage can expire and will be deleted automagically
 * - usage localStorageService.set(key, val, expire)
 * - expire is an integer defininig after how many hours the value expires
 * - when it expires, it is deleted from the localStorage
 */
app.config(($provide) => {
  $provide.decorator('localStorageService', ($delegate) => {
    
    //store original get & set methods
    var originalGet = $delegate.get,
      originalSet = $delegate.set;

    /**
     * extending the localStorageService get method
     *
     * @param key
     * @returns {*}
     */
    $delegate.get = (key) => {
      if(originalGet(key)) {
        var data = originalGet(key);

        if(data.expire) {
          var now = Date.now();

          // delete the key if it timed out
          if(data.expire < now) {
            $delegate.remove(key);
            return null;
          }

          return data.data;
        } else {
          return data;
        }
      } else {
        return null;
      }
    };

    /**
     * set
     * @param key               key
     * @param val               value to be stored
     * @param {int} expires     hours until the localStorage expires
     */
    $delegate.set = (key, val, expires) => {
      var expiryDate = null;

      if(angular.isNumber(expires)) {
        expiryDate = Date.now() + (1000 * 60 * 60 * expires);
        originalSet(key, {
          data: val,
          expire: expiryDate
        });
      } else {
        originalSet(key, val);
      }
    };

    return $delegate;
  });
});

Thanks for the feedback, will edit original post :)