Add emptyText property to SelectArrayInput

[MichaelTamm]

It would be nice to allow to specify what should be rendered inside a SelectArrayInput when no choice is selected. This feature is already present in the SelectInput.

For example:

const channelChoices = [
    {id: "email", name: "Email"},
    {id: "push", name: "Push Notification"},
];
<SelectArrayInput source="channels" choices={channelChoices} emptyText={<i>All Channels</i>} />

[djhi]

Indeed! Can you open a PR?

[Tomas025]

Hello, I'm a software engineering student I wanted to make my first contribution to an open source repository, can I act on this issue?

[djhi]

Hi @Tomas025, of course! Be aware that you'll need to:

• target the next branch as this is a new feature
• add a story for this new prop in https://github.com/marmelab/react-admin/blob/master/packages/ra-ui-materialui/src/input/SelectArrayInput.stories.tsx
• add tests in https://github.com/marmelab/react-admin/blob/master/packages/ra-ui-materialui/src/input/SelectArrayInput.spec.tsx using the story above
• add documentation for this new prop in https://github.com/marmelab/react-admin/blob/master/docs/SelectArrayInput.md