Question

I have the following code for generating a list of the next 12 months (inclusive), starting from today’s date:

function DateUtilFunctions() {
    var self = this;

    var monthNames = new Array();

    monthNames[0] = "January";
    monthNames[1] = "February";
    monthNames[2] = "March";
    monthNames[3] = "April";
    monthNames[4] = "May";
    monthNames[5] = "June";
    monthNames[6] = "July";
    monthNames[7] = "August";
    monthNames[8] = "September";
    monthNames[9] = "October";
    monthNames[10] = "November";
    monthNames[11] = "December";

    self.getNext12MonthNamesWithYear = function () {
        var months = new Array();
        var today = new Date(Date());

        var loopDate = new Date();
        loopDate.setTime(today.valueOf());

        var todayPlus12Months = new Date(today.setMonth(today.getMonth() + 12));

        while (loopDate.valueOf() < todayPlus12Months.valueOf()) {
            alert(loopDate);
            alert(loopDate.getMonth());
            var month = monthNames[loopDate.getMonth()];


            months.push(month + ' ' + loopDate.getFullYear());
            loopDate.setMonth(loopDate.getMonth() + 1);
        }

        return months;
    };
}

The result of calling getNext12MonthNamesWithYear() is:

• “May 2012”
• “July 2012”
• “August 2012”
• “May 2012”
• “July 2012”
• “August 2012”
• “September 2012”
• “October 2012”
• “November 2012”
• “December 2012”
• “January 2013”
• “February 2013”
• “March 2013”
• “April 2013”
• “May 2013”

As you can, the start of the list is a bit weird, in that “June” is missing, plus “May”, “July” and “August” appear twice.

Naturally I;m doing something very wrong here; could someone please help me out?

EDIT:

Based on micadelli’s comment, here is the solution I used:

function DateUtilFunctions() {
    var self = this;

    var monthNames = new Array();

    monthNames[0] = "January";
    monthNames[1] = "February";
    monthNames[2] = "March";
    monthNames[3] = "April";
    monthNames[4] = "May";
    monthNames[5] = "June";
    monthNames[6] = "July";
    monthNames[7] = "August";
    monthNames[8] = "September";
    monthNames[9] = "October";
    monthNames[10] = "November";
    monthNames[11] = "December";

    self.getNext12MonthNamesWithYear = function () {
        var months = new Array();
        var today = new Date();
        var tmpDate = new Date();
        var tmpYear = tmpDate.getFullYear();
        var tmpMonth = tmpDate.getMonth();
        var monthLiteral;

        for (var i = 0; i < 12; i++) {
            tmpDate.setMonth(tmpMonth + i);
            tmpDate.setFullYear(tmpYear);
            monthLiteral = monthNames[tmpMonth];

            months.push(monthLiteral + ' ' + tmpYear);

            tmpYear = (tmpMonth == 11) ? tmpYear + 1 : tmpYear;
            tmpMonth = (tmpMonth == 11) ? 0 : tmpMonth + 1;
        }

        return months;
    };
}

Answer 1

I dont see any reason why this wouldn’t work

function DateUtilFunctions() {
   var self = this;

   var monthNames = new Array();

   monthNames[0] = "January";
   monthNames[1] = "February";
   monthNames[2] = "March";
   monthNames[3] = "April";
   monthNames[4] = "May";
   monthNames[5] = "June";
   monthNames[6] = "July";
   monthNames[7] = "August";
   monthNames[8] = "September";
   monthNames[9] = "October";
   monthNames[10] = "November";
   monthNames[11] = "December";

   self.getNext12MonthNamesWithYear = function () {
     var months = new Array();
     var today = new Date();
     var tmpDate = new Date();
     var tmpYear = tmpDate.getFullYear();
     var tmpMonth = tmpDate.getMonth();
     var monthLiteral;

     for (var i = 0 ; i < 12 ; i++) {
        tmpDate.setMonth(tmpMonth + i);
        tmpDate.setFullYear(tmpYear);
        monthLiteral = monthNames[tmpMonth];
        months.push(monthLiteral + ' ' + tmpYear);
        tmpMonth = (tmpMonth == 11) ? 0 : tmpMonth+1;
        tmpYear = (tmpMonth == 11) ? tmpYear+1 : tmpYear;
     }

     return months;
   };
}

JS Bin
http://jsbin.com/aqezom