How to disable the SaveButton when the SimpleForm is invalid in a react-admin app?

Question

In a react-admin SimpleForm component validation is working fine when I click the save button. The field that is required is highlighted and marked red when I click the save button.

I'd like to add a className to the SaveButton as long as the form is invalid. This way I can make it clear to the user that he's not done with the form yet and prevent the user from clicking it.

This is a simplified version of such a SimpleForm.

import {
    required,
    //...
} from 'react-admin';

const UserCreateToolbar = props =>
    <Toolbar {...props}>
        <SaveButton
            label="user.action.save_and_show"
            redirect="show"
            submitOnEnter={true}
        />
    </Toolbar>;

export const UserCreate = props =>
    <Create {...props}>
        <SimpleForm
            toolbar={<UserCreateToolbar />}
        >
            <TextInput source="name" validate={[required()]} />
        </SimpleForm>
    </Create>;

Answer 1

Here's my own SaveButton component I came up with. It's working for me. Thanks @Gildas for pointing me in the right direction.

import React from 'react';
import PropTypes from 'prop-types';
import { reduxForm } from 'redux-form';
import { SaveButton } from 'react-admin';

const SaveButtonAware = ({ invalid, ...rest }) => (
    <SaveButton disabled={invalid} {...rest} />
);

SaveButtonAware.propTypes = {
    invalid: PropTypes.bool,
};

export default reduxForm({
    form: 'record-form',
})(SaveButtonAware);

Update. Apparently, this is working too. Not sure why.

import React from 'react';
import PropTypes from 'prop-types';
import { SaveButton } from 'react-admin';

const SaveButtonAware = ({ invalid, ...rest }) => (
    <SaveButton disabled={invalid} {...rest} />
);

SaveButtonAware.propTypes = {
    invalid: PropTypes.bool,
};

export default SaveButtonAware;