javascript date one year from now code example

Example 1: javascript get day of year

// `date` is a Date object
const dayOfYear = date => Math.floor((date - new Date(date.getFullYear(), 0, 0)) / (1000 * 60 * 60 * 24));

// Example
dayOfYear(new Date(2020, 04, 16));      // 137

Example 2: javascript get day of year from date

//Month -> 0= Jan, 11=Dec | myDate = 6 Dec 2019 10:45
var myDate = new Date(2019, 11, 06, 10, 45);
var dayInYear = Math.floor((myDate - new Date(myDate.getFullYear(), 0, 0)) / (1000 * 60 * 60 * 24));