Dates only with Angular-UI Bootstrap datepicker

gistfile1.js

    app.directive('datepickerLocaldate', ['$parse', function ($parse) {
        var directive = {
            restrict: 'A',
            require: ['ngModel'],
            link: link
        };
        return directive;

        function link(scope, element, attr, ctrls) {
            var ngModelController = ctrls[0];

            // called with a JavaScript Date object when picked from the datepicker
            ngModelController.$parsers.push(function (viewValue) {
                // undo the timezone adjustment we did during the formatting
                viewValue.setMinutes(viewValue.getMinutes() - viewValue.getTimezoneOffset());
                // we just want a local date in ISO format
                return viewValue.toISOString().substring(0, 10);
            });

            // called with a 'yyyy-mm-dd' string to format
            ngModelController.$formatters.push(function (modelValue) {
                if (!modelValue) {
                    return undefined;
                }
                // date constructor will apply timezone deviations from UTC (i.e. if locale is behind UTC 'dt' will be one day behind)
                var dt = new Date(modelValue);
                // 'undo' the timezone offset again (so we end up on the original date again)
                dt.setMinutes(dt.getMinutes() + dt.getTimezoneOffset());
                return dt;
            });
        }
    }]);

For those having problems with the returned date as undefined, change the ngModelController.$parsers part:

ngModelController.$parsers.push(function (viewValue) {
    // undo the timezone adjustment we did during the formatting
    viewValue.setMinutes(viewValue.getMinutes() - viewValue.getTimezoneOffset());
    // we just want a local date in ISO format
    var dateString = viewValue.toISOString().substring(0, 10);
    var dateParts = dateString.split("-");
    var newDate = new Date( dateParts[0], parseInt( dateParts[1] )-1, dateParts[2], 0, 0, 0 );
    return newDate;
});

The above solutions only work for timezones West of the UTC Timezone. Here's a fix that also works for timezones East of UTC so that dates don't appear one day behind:

 app.directive('datepickerLocaldate', ['$parse', function ($parse) {
    var directive = {
        restrict: 'A',
        require: ['ngModel'],
        link: link
    };
    return directive;

    function link(scope, element, attr, ctrls) {
        var ngModelController = ctrls[0];

        // called once user picks a date from datepicker with a JavaScript Date object
        ngModelController.$parsers.push(function (viewValue) {
            // undo the timezone adjustment we did during the formatting
            viewValue.setMinutes(viewValue.getMinutes() - viewValue.getTimezoneOffset());

            // get a local date in ISO format
            var dateString = viewValue.toISOString().substring(0, 10);
            var dateParts = dateString.split("-");
            var newDate = new Date( dateParts[0], parseInt( dateParts[1] )-1, dateParts[2], 0, 0, 0 );

            if (viewValue.getTimezoneOffset() < 0) {
                //case for Timezones East of UTC (floored to account for Indian Standard Time Zone on 30 minute delineations)
                newDate.setHours(newDate.getHours() - Math.floor(newDate.getTimezoneOffset()/60));
            } else {
                //case for Timezones West of UTC
                return newDate;
            }

            return newDate;
        });

        // called once user saves changes on a Title and passes the Date we had picked in the datepicker
        ngModelController.$formatters.push(function (modelValue) {
            if (!modelValue) {
                return undefined;
            }
            // date constructor will apply timezone deviations from UTC (i.e. if locale is West of UTC 'dt' will be one day behind)
            var dt = new Date(modelValue);

            // 'undo' the timezone offset again (so we end up on the original date again)
            if (dt.getTimezoneOffset() < 0) {
                //case for Timezones East of UTC
                dt.setMinutes(dt.getMinutes() - dt.getTimezoneOffset());
            } else {
                //case for Timezones West of UTC
                dt.setMinutes(dt.getMinutes() + dt.getTimezoneOffset());
            }

            return dt;
        });