Moment JS start and end of given month

Question

I need to calculate a JS date given year=2014 and month=9 (September 2014).

I tried this:

var moment = require('moment'); var startDate = moment( year+'-'+month+'-'+01 + ' 00:00:00' );             var endDate = startDate.endOf('month');             console.log(startDate.toDate());             console.log(endDate.toDate()); 

Both of logs show:

Tue Sep 30 2014 23:59:59 GMT+0200 (CEST) Tue Sep 30 2014 23:59:59 GMT+0200 (CEST) 

End date is correct but... why the start date is not?

Answer 1

That's because endOf mutates the original value.

Relevant quote:

Mutates the original moment by setting it to the end of a unit of time.

Here's an example function that gives you the output you want:

function getMonthDateRange(year, month) {     var moment = require('moment');      // month in moment is 0 based, so 9 is actually october, subtract 1 to compensate     // array is 'year', 'month', 'day', etc     var startDate = moment([year, month - 1]);      // Clone the value before .endOf()     var endDate = moment(startDate).endOf('month');      // just for demonstration:     console.log(startDate.toDate());     console.log(endDate.toDate());      // make sure to call toDate() for plain JavaScript date type     return { start: startDate, end: endDate }; } 

References:

• endOf()
• clone()
• Date from object

Answer 2

you can use this directly for the end or start date of the month

new moment().startOf('month').format("YYYY-DD-MM"); new moment().endOf("month").format("YYYY-DD-MM"); 

you can change the format by defining a new format