isSunday
import { isSunday } from "https://esm.sh/v135/date-fns@3.6.0/index.d.mts";@example
// Is 21 September 2014 Sunday?
const result = isSunday(new Date(2014, 8, 21))
//=> true
function isSunday<DateType extends Date>(date: DateType | number | string): boolean;