import { isMonday } from "https://deno.land/x/date_fns@v2.5.1/index.js";
Examples
// Is 22 September 2014 Monday?
var result = isMonday(new Date(2014, 8, 22))
//=> true
// Is 22 September 2014 Monday? var result = isMonday(new Date(2014, 8, 22)) //=> true