momentjs.com clone code example

Example 1: moment date add

var new_date = moment(startdate, "DD-MM-YYYY").add(5, 'days');

Example 2: moment js npm

moment.locale();         // en
moment().format('LT');   // 8:41 PM
moment().format('LTS');  // 8:41:43 PM
moment().format('L');    // 04/11/2020
moment().format('l');    // 4/11/2020
moment().format('LL');   // April 11, 2020
moment().format('ll');   // Apr 11, 2020
moment().format('LLL');  // April 11, 2020 8:41 PM
moment().format('lll');  // Apr 11, 2020 8:41 PM
moment().format('LLLL'); // Saturday, April 11, 2020 8:41 PM
moment().format('llll'); // Sat, Apr 11, 2020 8:41 PM
                         // undefined