how insert day in moment js code example

Example 1: moment check valid date

var date = moment("2016-10-19");
var check = date.isValid();
console.log(check);

Example 2: create moment duration

moment.duration(2, 'seconds');
moment.duration(2, 'minutes');
moment.duration(2, 'hours');
moment.duration(2, 'days');
moment.duration(2, 'weeks');
moment.duration(2, 'months');
moment.duration(2, 'years');
moment.duration('2', 'years'); // from 2.25.0

// or create from an object
moment.duration({
    seconds: 2,
    minutes: 2,
    hours: 2,
    days: 2,
    weeks: 2,
    months: '2',
    years: '2'
});

// or create from an iso 8601 string
moment.duration('P1Y2M3DT4H5M6S');
moment.duration('P1M');

// duration format strings with a space between days and rest is also supported.
moment.duration('7 23:59:59.999');