# Adapter

All adapters share the same set of methods. That enables you to switch an adapter for a different one, and everything will work just fine.

For every adapter, given method takes the very same argument(s) and behaves in similar fashion. Eventually, some adapters might throw (e.g. when connection to DB is lost), but generally speaking (for instance) `getItem` will always take a string as an argument (`key`), will return an Item (if found) or `undefined` (if not found). Always, regardless of the adapter being used at the moment.

Methods described on following pages explain what those methods consume and what is being returned. This will come in handy when you will be constructing your own adapters, to stay consistent with all other adapters.
