     _tasks = window.tasks
     _searchQuery = null
     _isReindexing = false
+    _cache = {}
 
     # TODO: retrieve the tasks sorted server-side
     _archivedTasks.sort (a, b) ->

        return tasksList.filter (task) -> task.tags.length is 0

    getByTags: (tags) ->

        {tasksList} = _getTaskLists()

        # returns all unselected tags if the tag filter is empty

            {cid, changes} = payload
            task = tasksListByCid[cid]

            # invalid cache
            _invalidCache task

            for field, value of changes
                task[field] = value

            # invalid cache if the tags have changed
            if changes.tags?
                _invalidCache task

            @emit 'change'

