React-admin: Multi-line notification messages - notifications

Question

How could i make react-admin to show a multi-line notification / error message on the snackbar?
Having the following dataProvider:
export default (type, resource, params) => {
throw new Error(`
Message line 1.
Message line 2.
Message line 3.
`);
};
That shows a single line message when loading a List component:
error notification screenshot

Answer 1

UPDATE 2022:
Since version 4 of react-admin, you can tell the useNotify hook, to use a multi line message passing the multiLine prop: https://marmelab.com/react-admin/useNotify.html#:~:text=multiLine%3A%20Set%20it%20to%20true%20if%20the%20notification%20message%20should%20be%20shown%20in%20more%20than%20one%20line.
End of UPDATE.
Ok, with the help of the docs I manage to do what I wanted.
Defining a custom Layout component to be used by the App component and passing it a custom Notification component.
// ./MyLayout.js
import React from 'react';
import { Layout } from 'react-admin';
import MyNotification from "../MyNotification";
const CustomLayout = props => (
<Layout {...props} notification={MyNotification} />
);
export default CustomLayout;
Then I pass a custom CSS class to the Notification component.
// ./MyNotification.js
import React from 'react';
import {withStyles} from '#material-ui/core/styles';
import {Notification} from 'react-admin';
// Allow multi-line messages to be displayed
const cssMsg = {
snackbarContent: {
whiteSpace: 'pre-wrap'
}
};
const MyNotification = withStyles(cssMsg)(({classes, ...props}) => (
<Notification {...props} className={classes.snackbarContent}/>
));
export default MyNotification;
error notification screenshot multi-line