How to enumerate dates between two dates in Moment

.add() is a mutator method, so the assignment in this line is unnecessary:

startDate = startDate.add(1, 'days');

You can just do this, and have the same effect:

startDate.add(1, 'days');

While it's name would imply the creation of a new Date object, the toDate() method really just returns the existing internal Date object.

So, none of your method calls are creating new Date or moment object instances. Fix that by using .clone() to get a new instance:

startDate = startDate.clone().add(1, 'days');

Or better yet, wrap the values in a call to moment() as Mtz suggests in a comment, and it will clone the instance, if the value is a moment object, or it will parse the input to create a new moment instance.

startDate = moment(startDate).add(1, 'days');

I think a date enumerator method should not change either of the arguments passed in. I'd create a separate variable for enumerating. I'd also compare the dates directly, rather than comparing strings:

var enumerateDaysBetweenDates = function(startDate, endDate) {
    var dates = [];

    var currDate = moment(startDate).startOf('day');
    var lastDate = moment(endDate).startOf('day');

    while(currDate.add(1, 'days').diff(lastDate) < 0) {
        console.log(currDate.toDate());
        dates.push(currDate.clone().toDate());
    }

    return dates;
};

Got it for you:

var enumerateDaysBetweenDates = function(startDate, endDate) {
    var now = startDate.clone(), dates = [];

    while (now.isSameOrBefore(endDate)) {
        dates.push(now.format('M/D/YYYY'));
        now.add(1, 'days');
    }
    return dates;
};

Referencing now rather than startDate made all the difference.

If you're not after an inclusive search then change .isSameOrBefore to .isBefore

Fiddle: http://jsfiddle.net/KyleMuir/sRE76/118/