d-date-utils.html

<link rel="import" href="../polymer/polymer.html">
<polymer-element name="d-date-utils" hidden>
  <script>
    Polymer({
      addDays: function(d, days) {
        var newDate = this.clone(d);
        newDate.setDate(d.getDate() + days);
        return newDate;
      },

      addMonths: function(d, months) {
        var newDate = this.clone(d);
        newDate.setMonth(d.getMonth() + months);
        return newDate;
      },

      clone: function(d) {
        return new Date(d.getTime());
      },

      getDaysInMonth: function(d) {
        var resultDate = this.getFirstDayOfMonth(d);

        resultDate.setMonth(resultDate.getMonth() + 1);
        resultDate.setDate(resultDate.getDate() - 1);

        return resultDate.getDate();
      },

      getFirstDayOfMonth: function(d) {
        return new Date(d.getFullYear(), d.getMonth(), 1);
      },

      getWeekArray: function(d) {
        var dayArray = [];
        var daysInMonth = this.getDaysInMonth(d);
        var daysInWeek;
        var emptyDays;
        var firstDayOfWeek;
        var week;
        var weekArray = [];

        for (var i = 1; i <= daysInMonth; i++) {
          dayArray.push(new Date(d.getFullYear(), d.getMonth(), i));
        };

        while (dayArray.length) {
          firstDayOfWeek = dayArray[0].getDay();
          daysInWeek = 7 - firstDayOfWeek;
          emptyDays = 7 - daysInWeek;
          week = dayArray.splice(0, daysInWeek);

          for (var i = 0; i < emptyDays; i++) {
            week.unshift(null);
          };

          weekArray.push(week);
        }

        return weekArray;
      },

      isEqualDate: function(d1, d2) {
        return d1 && d2 &&
          (d1.getFullYear() === d2.getFullYear()) &&
          (d1.getMonth() === d2.getMonth()) &&
          (d1.getDate() === d2.getDate());
      },

      isEqualMonth: function(d1, d2) {
        return d1 && d2 &&
          (d1.getFullYear() === d2.getFullYear()) &&
          (d1.getMonth() === d2.getMonth());
      },

      monthDiff: function(d1, d2) {
        var m;
        m = (d1.getFullYear() - d2.getFullYear()) * 12;
        m += d1.getMonth();
        m -= d2.getMonth();
        return m;
      }

    })

/**
 * Transform a supplied input date using a specified format
 * @param  {date} input  
 * @param  {string} format
 * @return {date}
 */
PolymerExpressions.prototype.date = function (input, format) {
    var date = new Date(input),
        day = date.getDate(),
        month = date.getMonth() + 1,
        year = date.getFullYear(),
        hours = date.getHours(),
        minutes = date.getMinutes(),
        seconds = date.getSeconds();

    if (!format) {
        format = "MM/dd/yyyy";
    }

    format = format.replace("MM", month.toString().replace(/^(\d)$/, '0$1'));

    if (format.indexOf("yyyy") > -1) {
        format = format.replace("yyyy", year.toString());
    } else if (format.indexOf("yy") > -1) {
        format = format.replace("yy", year.toString().substr(2, 2));
    }

    format = format.replace("dd", day.toString().replace(/^(\d)$/, '0$1'));

    if (format.indexOf("t") > -1) {
        if (hours > 11) {
            format = format.replace("t", "pm");
        } else {
            format = format.replace("t", "am");
        }
    }

    if (format.indexOf("HH") > -1) {
        format = format.replace("HH", hours.toString().replace(/^(\d)$/, '0$1'));
    }

    if (format.indexOf("hh") > -1) {
        if (hours > 12) {
            hours -= 12;
        }

        if (hours === 0) {
            hours = 12;
        }
        format = format.replace("hh", hours.toString().replace(/^(\d)$/, '0$1'));
    }

    if (format.indexOf("mm") > -1) {
        format = format.replace("mm", minutes.toString().replace(/^(\d)$/, '0$1'));
    }

    if (format.indexOf("ss") > -1) {
        format = format.replace("ss", seconds.toString().replace(/^(\d)$/, '0$1'));
    }

    return format;
};
  </script>
</polymer-element>