how to take out day month from date in javascript 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: how to get only month and year in js

let dateObj = new Date();

let myDate = (dateObj.getUTCFullYear()) + "/" + (dateObj.getMonth() + 1)+ "/" + (dateObj.getUTCDate());