loopback.createDataSource({localStorage: 'mydb', connector: loopback.Memory});

...will allow you to read/write/replicate/etc models with the browser's localStorage.

LoopBack replication/sync is similar to PouchDB. The important distinction is that loopback can sync with any connector that supports the basic crud methods:

http://docs.strongloop.com/display/DOC/Data+sources+and+conn...