Can I use ng-model with an isolated scope?


I am creating simple ui-datetime directive. It splits javascript Date object into _date, _hours and _minutes parts. _date uses jquery ui datepicker, _hours and _minutes - number inputs.

angular.module("ExperimentsModule", [])
    .directive("uiDatetime", function () {
    return {
        restrict: 'EA',
        replace: true,
        template: '<div class="ui-datetime">' +
            '<input type="text" ng-model="_date" class="date">' +
            '<input type="number" ng-model="_hours" min="0" max="23" class="hours">' +
            '<input type="number" ng-model="_minutes" min="0" max="59" class="minutes">' +
            '<br />Child datetime1: {{datetime1}}' +
        require: 'ngModel',
        scope: true,
        link: function (scope, element, attrs, ngModelCtrl) {
            var elDate = element.find('');

            ngModelCtrl.$render = function () {
                var date = new Date(ngModelCtrl.$viewValue);
                var fillNull = function (num) {
                    if (num < 10) return '0' + num;
                    return num;
                scope._date = fillNull(date.getDate()) + '.' + fillNull(date.getMonth() + 1) + '.' + date.getFullYear();
                scope._hours = date.getHours();
                scope._minutes = date.getMinutes();

                dateFormat: '',
                onSelect: function (value, picker) {
                    scope._date = value;

            var watchExpr = function () {
                var res = scope.$eval('_date').split('.');
                if (res.length == 3) return new Date(res[2], res[1] - 1, res[0], scope.$eval('_hours'), scope.$eval('_minutes'));
                return 0;
            scope.$watch(watchExpr, function (newValue) {
            }, true);

function TestController($scope) {
    $scope.datetime1 = new Date();


On github:

As far as I understand - best practice when you create a new component is to use isolated scope.

When I tried to use isolated scope - nothing works. ngModel.$viewValue === undefined.

When I tried to use new scope (my example, not so good variant imho) - ngModel uses value on newly created scope.

Of course I can create directive with isolated scope and work with ngModel value through "=expression" (example). But I think that working with ngModelController is a better practice.

My questions:

  1. Can I use ngModelController with isolated scope?
  2. If it is not possible which solution is better for creating such component?

Replacing scope: true with scope: { datetime1: '=ngModel'} in your first fiddle seems to work fine -- fiddle. Unfortunately, the link to your "example" fiddle is broken, so I'm not sure what you tried there.

So, it would seem that ngModelController can be used with an isolate scope.

Here's a smaller fiddle that uses ng-model in the HTML/view, an isolate scope, and $setViewValue in the link function: fiddle.

Update: I just discovered something rather interesting: if the isolate scope property is given a different name -- e.g., say dt1 instead of datetime1 -- scope: { dt1: '=ngModel'} -- it no longer works! I'm guessing that when we require: 'ngModel', the ngModelController uses the name in the HTML/view (i.e., the ng-model attribute value) to create a property on the isolate scope. So if we specify the same name in the object hash, all is well. But if we specify a different name, that new scope property (e.g., dt1) is not associated with the ngModelController we required.

Here's an updated fiddle.