var dates = ["2-2015", "1-2015", "1-2014", "10-2016", "6-2012"];

var parseDate = function(date) {
    return date.split("-").map(function(ele) {
        return parseInt(ele);
    });
};

dates.sort(function(a, b) {
    a = parseDate(a);
    b = parseDate(b);

    var MONTH = 0,
        YEAR = 1;

    return a[YEAR] === b[YEAR] ? (
            a[MONTH] < b[MONTH] ? -1 : (a[MONTH] === b[MONTH] ? 0 : 1)
        ) :
        (
            a[YEAR] < b[YEAR] ? -1 : (a[YEAR] === b[YEAR] ? 0 : 1)
        );

});