getDaysInYear
import { getDaysInYear } from "https://esm.sh/v135/date-fns@3.6.0/index.d.mts";@example
// How many days are in 2012?
const result = getDaysInYear(new Date(2012, 0, 1))
//=> 366
function getDaysInYear<DateType extends Date>(date: DateType | number | string): number;