Gets the date string in ISO format (YYYY-MM-DD) from a Date object or a date-like value.
getDateString(new Date('2023-10-01')); // '2023-10-01'
getDateString('2023-10-01'); // '2023-10-01'
getDateString(1738358400000); // '2023-10-01'
getDateString(new Date('invalid-date')); // undefined
getDateString(null); // undefined
getDateString(undefined); // undefined
Gets the date string in ISO format (YYYY-MM-DD) from a Date object or a date-like value.