How to format inital date value using AngularJS ui-date directive?

The problem is that the "date" is just a string, Angular wants a native Date object (or a timestamp).

I've found two ways of dealing with this: Scrub the data right away or watch the variable and reassign its type.

My preferred solution is to munge the data when it's brought in. Since I know the object has a date, I just scrub the JSON data from the $http success promise like this:

$http.get('data.json').success(function(data) {
    data.date = Date.parse(data.date);
    $scope.model = data;
}

That converts the data before it's assigned to $scope, so Angular will see $scope.model.date as a native JS Date object format it correctly.

The other solution is to specifically $watch the variable's type. Somewhere in the controller, add this:

$scope.$watch('model.date', function() {
    if (typeof $scope.model.date === 'string') {
        $scope.model.date = Date.parse($scope.model.date);
    }
});

That checks the type everytime $scope.model.date is modified. Obviously, that's more overhead, but might be useful in some cases.

I had the same issue. Here is what I did using Jquery-UI calendar with Angularjs

date format was "2015-03-24T04:00:00"

First trim the date string to get only year, month, and date.

var date = "2015-03-24T04:00:00"
var formattedDate = date.match(/[\d-]+/).pop();
// formattedDate is now "2015-03-24" which is passed into
// the directive below as the input.$modelValue.

Now, inside your directive or controller do the following...

// Here is directive example.
link: function( scope, element, attrs, input ){

  element.datepicker( optionsObjectHere );
  setInitialDateFormatOnInput();

  function setInitialDateFormatOnInput(){
    setTimeout(function(){ // This timeout is required to delay the directive for the input.modelValue to resolve, however, no actual delay occurs!
      element.datepicker( "setDate", formatToJqueryUIDateFormat());
    });
  }

  function formatToJqueryUIDateFormat(){
    return $.datepicker.parseDate( 'yy-mm-dd', input.$modelValue );
    // 'yy-mm-dd' needs to match the input.$modelValue format from above. 
  }
} // link

This is how I use the entire jquery UI on my inputs.

HTML

<input type="text" class="inline" ng-model="inputValue" my-calendar-popup="calendarOptions" />

Where calendarOptions is the following object

  var calendarOptions = { minDate: 0, buttonImage: "calendar-icon.png", buttonImageOnly: 'true', showOn: "both", dateFormat: "MM d, yy" };

DIRECTIVE

app.directive('myCalendarPopup', function(){

  var defaultOptions = { minDate: 0, buttonImage: "calendar-icon.png",   buttonImageOnly: 'true', showOn: "both", dateFormat: "MM d, yy" };
  // defaultOptions just in case someone doesn't pass in options.

  return {
    require:'?ngModel',
    restrict: 'A',

    link: function( scope, element, attrs, input ){
      if ( !input ){ return; } // If no ngModel then return;

      element.datepicker( createCalendarOptions());
      setInitialDateFormatOnInput();

      function createCalendarOptions(){
        if( !attrs.rsCalendarPopup ){ return addRequiredJqueryFunction( defaultOptions );}
        return formatOptions();
      }

      function formatOptions() {
        var options = scope.$eval( attrs.rsCalendarPopup );
        // Turn string into object above.
        return addRequiredJqueryFunction( options );
      }

      function addRequiredJqueryFunction( options ){
        options.onSelect = changeDate;
        // add onSelect to passed in object and reference local changeDate function, which will update changes to input.$modelValue.
        return options;
      }

      function changeDate( date ){
        input.$setViewValue( date );
      }

      function setInitialDateFormatOnInput(){
        setTimeout(function(){
        // This timeout is required to delay the directive for the input.modelValue to resolve.
        // However, there is no actual timeout time. This is a must to get
        // Angular to behave.
          element.datepicker( "setDate", formatToJqueryUIDateFormat());
        });
      }

      function formatToJqueryUIDateFormat(){
        return $.datepicker.parseDate( 'yy-mm-dd', input.$modelValue );
        // 'yy-mm-dd' is not the format you want the calendar to be
        // it is the format the original date shows up as.
        // you set your actual formatting using the calendar options at
        // the top of this directive or inside the passed in options.
        // The key is called dateFormat, in this case it's set as
        // dateFormat: "MM d, yy" which makes June 30, 2015.
      }
    } // link
  } // return
});

Note: I can only get this to work in it's displayed configuration. I have added it to a controller, and even a directive controller and could not recreate the initial date condition. I have not found out why this is yet. Perhaps this solution works only within a link function that is embedded in another isolated scope directive and works due to specific timing.