     @props.onChange date
 
   renderMonthSelector: ->
-    months = _.map monthMap, (month) -> option value: month[0], month[1]
+    months = _.map monthMap, (month) -> option
+      value: month[0], key: month[0]
+    , month[1]
+
     return select
       className: "input-date-month"
       value: @state.value.getMonth()


  renderYearSelector: ->
    years = _.map [@state.currentYear..1900], (year) ->
      option value: year, year
    return select
      className: "input-date-year"
      value: @state.value.getFullYear()

    , months

  renderDaySelector: ->
    days = [
      1..daysInMonth(@state.value.getMonth() + 1, @state.value.getFullYear())
    ]
    dayOptions = _.map days, (day) -> option value: day, key: day, day
    return select
      className: "input-date-day"
      value: @state.value.getDate()
