[removed] get all months between two dates?

Question

I have two date strings like this:

var startDate = \'2012-04-01\';
var endDate = \'2014-11-01\';

And I want to end up with an array of stri

Answer 1

You are handling "logical" jumps, so you doesn't actually need timing arthmetics. So this is a simple counting problem:

var startDate = '2012-04-01';
var endDate = '2014-11-01';
var dates = [];

var d0 = startDate.split('-');
var d1 = endDate.split('-');

for (
    var y = d0[0];
    y <= d1[0];
    y++
) {
    for (
        var m = d0[1];
        m <= 12;
        m++
    ) {
        dates.push(y+"-"+m+"-1");
        if (y >= d1[0] && m >= d1[1]) break;
    };
    d0[1] = 1;
};

console.log(dates);

Answer 2

If loading an extra library isn't a problem, you could always try the awesome MomentJS.
Gives for very clean and powerful date manipulation.

var startDate = moment('2012-04-01');
var endDate = moment('2014-11-01');

var dates = [];
endDate.subtract(1, "month"); //Substract one month to exclude endDate itself

var month = moment(startDate); //clone the startDate
while( month < endDate ) {
    month.add(1, "month");
    dates.push(month.format('YYYY-MM-DD'));
}

console.log(dates);

JSFiddle here

Answer 3

This is my solution, with help of math and O(n)

determineMonthInInterval(startDate, endDate) {

    let startYear = startDate.getFullYear();
    let endYear = endDate.getFullYear();

    let startMonth = startDate.getMonth() + 1;
    let endMonth = endDate.getMonth() + 1;

    let monthAmount = (endMonth - startMonth) + 1 + (12 * (endYear - startYear));

    let dates = [];
    let currMonth = startMonth;
    let currYear = startYear;
    for( let i=0; i<monthAmount; i++){
        
        let date = new Date(currYear + "/"+currMonth+"/1");
        dates.push(date);

        currYear = startYear + Math.floor((startMonth+i) / 12);
        currMonth = (currMonth) % 12 +1;

    }

    return dates;
}

Answer 4

This should produce the desired output:

function dateRange(startDate, endDate) {
  var start      = startDate.split('-');
  var end        = endDate.split('-');
  var startYear  = parseInt(start[0]);
  var endYear    = parseInt(end[0]);
  var dates      = [];

  for(var i = startYear; i <= endYear; i++) {
    var endMonth = i != endYear ? 11 : parseInt(end[1]) - 1;
    var startMon = i === startYear ? parseInt(start[1])-1 : 0;
    for(var j = startMon; j <= endMonth; j = j > 12 ? j % 12 || 11 : j+1) {
      var month = j+1;
      var displayMonth = month < 10 ? '0'+month : month;
      dates.push([i, displayMonth, '01'].join('-'));
    }
  }
  return dates;
}

Just call it with your existing date format:

dateRange('2013-11-01', '2014-06-01')
// ["2013-11-01", "2013-12-01", "2014-01-01", "2014-02-01", "2014-03-01", "2014-04-01", "2014-05-01", "2014-06-01", "2014-07-01", "2014-08-01", "2014-09-01", "2014-10-01", "2014-11-01", "2014-12-01"]