Creating an AngularJs directive to alter input formatting

Question

Creating an AngularJs directive to alter input formatting

I am looking to achieve the following:

Within my controller model, I have a date object that I want users to be able to modify. I need to provide them with two input fields - one for modifying the date and the other for modifying the time. Both input fields should interact with the same date model.

<input ng-model="model.date" date-format="YYYY-MM-DD">
<input ng-model="model.date" date-format="HH:mm:SS">

I have not been able to find any specific guidance on this particular binding requirement. Typically, the ng-model directive manages the value of the input field. However, in this case, I want to override this value with my own formatting. Additionally, any changes made by the user should be parsed and updated back into the date object.

Given the complexities of date manipulation in vanilla JavaScript, I have opted to utilize moment.js for formatting and parsing dates and strings.

My current approach is as follows:

app.directive('dateFormat', function() {
    return {
        restrict: 'A',
        link: function(scope, el, at) {
            var format = at.dateFormat;
            scope.$watch(at.ngModel, function(date) {
                var result = moment(date).format(format);
                el.val(result);
            });
        }
    };
});

However, I have encountered issues when attempting to change the input value within the browser, resulting in NaN:NaN...

Some questions that I have regarding this implementation include:

How can I effectively model this functionality?
Does this approach align with Angular's philosophy, or am I veering off course?
Is it possible to seamlessly integrate ng-model and my custom date-format directive?
Are there simpler alternatives for achieving this desired outcome?

javascript angularjs

Answer 1

Answer №1

If you're in search of a solution, a filter might be the answer:

//Within your controller
$scope.modelDate = $filter('date')(dateToFormat, "YYYY-MM-DD");

//In your view
<input ng-model="modelDate" type="text">

It's worth noting that your initial approach wasn't entirely wrong, as the formatting could get disrupted when users input text. To solve this, you need to utilize ngModel, which interacts with Directives through a specific API and can be accessed directly during the linking process.

To adapt your code, consider implementing something like this:


return {
require: 'ngModel',
link: function(scope, element, attrs, ngModelController) {
ngModelController.$parsers.push(function(data) {
//View -> Model
return data;
});
ngModelController.$formatters.push(function(data) {
//Model -> View
return $filter('date')(data, "YYYY-MM-DD");
});
}
}

For more details, check out this resource

Answer 2

If you're in search of a solution, a filter might be the answer:

//Within your controller
$scope.modelDate = $filter('date')(dateToFormat, "YYYY-MM-DD");

//In your view
<input ng-model="modelDate" type="text">

It's worth noting that your initial approach wasn't entirely wrong, as the formatting could get disrupted when users input text. To solve this, you need to utilize ngModel, which interacts with Directives through a specific API and can be accessed directly during the linking process.

To adapt your code, consider implementing something like this:


return {
require: 'ngModel',
link: function(scope, element, attrs, ngModelController) {
ngModelController.$parsers.push(function(data) {
//View -> Model
return data;
});
ngModelController.$formatters.push(function(data) {
//Model -> View
return $filter('date')(data, "YYYY-MM-DD");
});
}
}

For more details, check out this resource

Answer 3

Answer №2

After encountering a similar issue, I dedicated my time to researching and experimenting to devise a unique solution. This solution involves executing the desired formatting and validation on 'blur' rather than after every keystroke. Detailed information about each step can be found within the comment tags. It is essential to have moment.js for date validation.

myApp.directive('validDate', function ($filter, $window, $parse, $timeout) {
return {
    require: '?ngModel',
    restrict: 'A',
    compile: function () {
        var moment = $window.moment;
        var getter, setter;
        return function (scope, element, attrs, ngModel) {
            //Declaring the getter and setter
            getter = $parse(attrs.ngModel);
            setter = getter.assign;
            //Set the initial value to the View and the Model
            ngModel.$formatters.unshift(function (modelValue) {
                if (!modelValue) return "";
                var retVal = $filter('date')(modelValue, "MM/dd/yyyy");
                setter(scope, retVal);
                console.log('Set initial View/Model value from: ' + modelValue + ' to ' + retVal);
                return retVal;
            });

            // If the ngModel directive is used, then set the initial value and keep it in sync
            if (ngModel) {
                element.on('blur', function (event) {
                    var date = moment($filter('date')(element.val(), "MM/dd/yyyy"));
                    // if the date entered is a valid date then save the value
                    if (date && moment(element.val(), "MM/DD/YYYY").isValid() && date <= moment() && date >= moment("01/01/1900")) {
                        element.css('background', 'white');
                        element[0].value = $filter('date')(date.toDate(), "MM/dd/yyyy");
                        console.log('change value to ' + element.val());
                        var newValue = element.val();
                        scope.$apply(function () {
                            setter(scope, newValue);
                        });
                    } else { //show an error and clear the value
                        console.log('INCORRECT VALUE ENTERED');
                        element.css('background', 'pink');
                        element[0].value = "";
                        scope.$apply(function () {
                            setter(scope, '');
                        });
                    }
                });
             }
         };
      }
  }; });

To implement this directive in the View, use the following syntax:

<input type="text" ng-model="member.BirthDate" required valid-date />

Answer 4

After encountering a similar issue, I dedicated my time to researching and experimenting to devise a unique solution. This solution involves executing the desired formatting and validation on 'blur' rather than after every keystroke. Detailed information about each step can be found within the comment tags. It is essential to have moment.js for date validation.

myApp.directive('validDate', function ($filter, $window, $parse, $timeout) {
return {
    require: '?ngModel',
    restrict: 'A',
    compile: function () {
        var moment = $window.moment;
        var getter, setter;
        return function (scope, element, attrs, ngModel) {
            //Declaring the getter and setter
            getter = $parse(attrs.ngModel);
            setter = getter.assign;
            //Set the initial value to the View and the Model
            ngModel.$formatters.unshift(function (modelValue) {
                if (!modelValue) return "";
                var retVal = $filter('date')(modelValue, "MM/dd/yyyy");
                setter(scope, retVal);
                console.log('Set initial View/Model value from: ' + modelValue + ' to ' + retVal);
                return retVal;
            });

            // If the ngModel directive is used, then set the initial value and keep it in sync
            if (ngModel) {
                element.on('blur', function (event) {
                    var date = moment($filter('date')(element.val(), "MM/dd/yyyy"));
                    // if the date entered is a valid date then save the value
                    if (date && moment(element.val(), "MM/DD/YYYY").isValid() && date <= moment() && date >= moment("01/01/1900")) {
                        element.css('background', 'white');
                        element[0].value = $filter('date')(date.toDate(), "MM/dd/yyyy");
                        console.log('change value to ' + element.val());
                        var newValue = element.val();
                        scope.$apply(function () {
                            setter(scope, newValue);
                        });
                    } else { //show an error and clear the value
                        console.log('INCORRECT VALUE ENTERED');
                        element.css('background', 'pink');
                        element[0].value = "";
                        scope.$apply(function () {
                            setter(scope, '');
                        });
                    }
                });
             }
         };
      }
  }; });

To implement this directive in the View, use the following syntax:

<input type="text" ng-model="member.BirthDate" required valid-date />

Creating an AngularJs directive to alter input formatting

Answer №1

Answer №2

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