Unify the date typing for ReactDatePickerProps in EuiDatePicker Typescript

[TAYTS]

Is it possible to add null to the ReactDatePickerProps startDate props as Typescript complaint about tying between the moment.Moment | null and moment.Moment | undefined?

I faced this issue when trying to use useState hook:

const [startDate, setStartDate] = useState<moment.Moment | null>(moment());

<EuiDatePickerRange
    startDateControl={
        <EuiDatePicker
            selected={startDate}
            onChange={(date) => setStartDate(date)}
            startDate={startDate as moment.Moment | undefined}
            aria-label="Start date"
         />
    }
    endDateControl={<EuiDatePicker />}
/>

Although the issue can simply resolved by just casting to moment.Moment | undefined but I think it might be nicer to unify the typing since most of the date has the moment.Moment | null type.

Below are the code reference:

eui/src/components/date_picker/react-datepicker.d.ts

Lines 103 to 106 in 55252c8

	onChange?(
	date: moment.Moment | null,
	event?: React.SyntheticEvent<any>
	): void;

eui/src/components/date_picker/react-datepicker.d.ts

Line 138 in 55252c8

selected?: moment.Moment | null;

eui/src/components/date_picker/react-datepicker.d.ts

Line 161 in 55252c8

startDate?: moment.Moment;

[chandlerprall]

Makes sense!