[Autocomplete] Provide options to control behaviour when cleared

• I have searched the issues of this repository and believe that this is not a duplicate.

Summary 💡

While this issue is similar to #18280 I don’t believe its a duplicate.

It would be good if developers had the ability to customize the behavior of the autocomplete when the selection is cleared via the Clear button.

Options:

• openOnClear={false} - revert the Autocomplete to it’s null/placeholder state
• onClear event handler

Examples 🌈

<Autocomplete
    options={["A", "B", "C", "D"]}
    openOnClear={false}
    renderInput={params => (
        <TextField {...params} label="Letter" variant="outlined" fullWidth />
    )}
/>

[oliviertassinari]

@MartinSkovsen Thanks for the extra details, feel free to override this behavior in your application. I assume you would need to call prevent default on mouse down to keep the focus where it was, and extend the component to support https://next.material-ui.com/components/autocomplete/#events.

[MartinSkovsen]

Good point. I don’t have any specific expectation for the activeElement; Keeping the current functionality is certainly a sensible default. However, I would like to optionally provide an alternative activeElement. Think of this scenario:

I have an optional entry in my form. The user uses a combobox for providing the desired value. The user might decide to delete the selected value for which ever reason, and then want to be out of focus. I currently have this case, and ideally I don’t interfere with how the component works, particularly since a work around will be devious (and surely confusing). – Perhaps this is just an anti pattern suggestion…