import { getISOWeeksInYear } from "https://deno.land/x/date_fns@v2.5.1/index.js";
Examples
// How many weeks are in ISO week-numbering year 2015?
var result = getISOWeeksInYear(new Date(2015, 1, 11))
//=> 53
// How many weeks are in ISO week-numbering year 2015? var result = getISOWeeksInYear(new Date(2015, 1, 11)) //=> 53