Add localStorage data provider

[fzaninotto]

An admin can use localStorage for part of or all the underlying data. A localStorage dataProvider opens the possibility to build local-first admins.

import localStorageDataProvider from 'ra-data-local-storage';
const dataProvider = localStorageDataProvider();

Uses ra-data-fakerest under the hood, synchronizing changes between the FakeRest (in-memory) and localStorage databases. It also hides warnings for undefined collections, and allows the addition of a record to an undefined collection.

Note that localStorage is limited to 5MB in size.

[djhi]

I don't really get why it needs fakerest. Can you elaborate ?

[fzaninotto]

To avoid duplicating the code needed to handle dataProvider requests in an in memory database. Basically this entire file:

https://github.com/marmelab/FakeRest/blob/master/src/Collection.js