I would love an example of how to configure the admin-on-rest left-bar menu with sub-menus.
Documentation: https://marmelab.com/admin-on-rest/Admin.html#menu
This is not supported out of the box in aor. However, you should be able to make your own menu and integrate material-ui sub menus in it. There's nothing special about it. Remember that your menus should use a containerElement
to use React-router Link though.
<MenuItem
containerElement={<Link to="/profile" />}
.../>
Here is an example using the demo app on codesandbox: https://codesandbox.io/s/88ok152q08
Note the custom Menu in menu.js
.
Also bear in mind that this menu will require a bit more work in order to adapt for mobile devices