Mike Pateras Mike Pateras - 26 days ago 20
jQuery Question

AngularJS - Attribute directive input value change

I've got an AngularJS attribute directive, and I would like to take an action any time its parent input's value changes. Right now I'm doing it with jQuery:

angular.module("myDirective", [])
.directive("myDirective", function()
{
return {
restrict: "A",
scope:
{
myDirective: "=myDirective"
},
link: function(scope, element, attrs)
{
element.keypress(function()
{
// do stuff
});
}
};
});


Is there a way to do this without jQuery? I'm finding the keyPress event isn't doing exactly what I want it to, and while I'm sure I'll come up with a solution, I get a little nervous when I resort to using jQuery in an Angular project.

So what's the Angular way to do this?

Answer

There's a great example in the AngularJS docs here:

http://docs.angularjs.org/api/ng.directive:ngModel.NgModelController

It's very well commented and should get you pointed in the right direction.

A simple example, maybe more so what you're looking for is below:

http://jsfiddle.net/mb98y/

HTML

<div ng-app="myDirective" ng-controller="x">
    <input type="text" ng-model="test" my-directive>
</div>

JavaScript

angular.module('myDirective', [])
    .directive('myDirective', function () {
    return {
        restrict: 'A',
        link: function (scope, element, attrs) {
            scope.$watch(attrs.ngModel, function (v) {
                console.log('value changed, new value is: ' + v);
            });
        }
    };
});

function x($scope) {
    $scope.test = 'value here';
}

Edit Same thing, doesn't require ngModel (http://jsfiddle.net/mb98y/1/):

JavaScript:

angular.module('myDirective', [])
    .directive('myDirective', function () {
    return {
        restrict: 'A',
        scope: {
            myDirective: '='
        },
        link: function (scope, element, attrs) {
            // set the initial value of the textbox
            element.val(scope.myDirective);
            element.data('old-value', scope.myDirective);

            // detect outside changes and update our input
            scope.$watch('myDirective', function (val) {
                element.val(scope.myDirective);
            });

            // on blur, update the value in scope
            element.bind('propertychange keyup paste', function (blurEvent) {
                if (element.data('old-value') != element.val()) {
                    console.log('value changed, new value is: ' + element.val());
                    scope.$apply(function () {
                        scope.myDirective = element.val();
                        element.data('old-value', element.val());
                    });
                }
            });
        }
    };
});

function x($scope) {
    $scope.test = 'value here';
}
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