Update Angular model after setting input value wit

Question

I have this simple scenario:

Input element which value is changed by jQuery's val() method.

I am trying to update the angular model with the value that jQuery set. I tried to write a simple directive, but it's not doing what I want.

Here's the directive:

var myApp = angular.module('myApp', []);
myApp.directive('testChange', function() {
    return function(scope, element, attrs) {        
        element.bind('change', function() {
            console.log('value changed');
        })
    }
})

this is the jQuery part:

$(function(){
    $('button').click(function(){
        $('input').val('xxx');
    })
})

and html:

<div ng-app="myApp">
    <div ng-controller="MyCtrl">
        <input test-change ng-model="foo" />
        <span>{{foo}}</span>
    </div>
</div>

<button>clickme</button>

Here is the fiddle with my try:
http://jsfiddle.net/U3pVM/743/

Can someone please point me in the right direction?

Answer 1

ngModel listens for "input" event, so to "fix" your code you'd need to trigger that event after setting the value:

$('button').click(function(){
    var input = $('input');
    input.val('xxx');
    input.trigger('input'); // Use for Chrome/Firefox/Edge
    input.trigger('change'); // Use for Chrome/Firefox/Edge + IE11
});

For the explanation of this particular behaviour check out this answer that I gave a while ago: "How does AngularJS internally catch events like 'onclick', 'onchange'?"

---

But unfortunately, this is not the only problem you have. As pointed out with other post comments, your jQuery-centric approach is plain wrong. For more info take a look at this post: How do I “think in AngularJS” if I have a jQuery background?).

Answer 2

If you are using IE, you have to use: input.trigger("change");

Answer 3

I've written this little plugin for jQuery which will make all calls to .val(value) update the angular element if present:

(function($, ng) {
  'use strict';

  var $val = $.fn.val; // save original jQuery function

  // override jQuery function
  $.fn.val = function (value) {
    // if getter, just return original
    if (!arguments.length) {
      return $val.call(this);
    }

    // get result of original function
    var result = $val.call(this, value);

    // trigger angular input (this[0] is the DOM object)
    ng.element(this[0]).triggerHandler('input');

    // return the original result
    return result; 
  }
})(window.jQuery, window.angular);

Just pop this script in after jQuery and angular.js and val(value) updates should now play nice.

---

Minified version:

!function(n,t){"use strict";var r=n.fn.val;n.fn.val=function(n){if(!arguments.length)return r.call(this);var e=r.call(this,n);return t.element(this[0]).triggerHandler("input"),e}}(window.jQuery,window.angular);

---

Example:

// the function
(function($, ng) {
  'use strict';
  
  var $val = $.fn.val;
  
  $.fn.val = function (value) {
    if (!arguments.length) {
      return $val.call(this);
    }
    
    var result = $val.call(this, value);
    
    ng.element(this[0]).triggerHandler('input');
    
    return result;
    
  }
})(window.jQuery, window.angular);

(function(ng){ 
  ng.module('example', [])
    .controller('ExampleController', function($scope) {
      $scope.output = "output";
      
      $scope.change = function() {
        $scope.output = "" + $scope.input;
      }
    });
})(window.angular);

(function($){  
  $(function() {
    var button = $('#button');
  
    if (button.length)
      console.log('hello, button');
    
    button.click(function() {
      var input = $('#input');
      
      var value = parseInt(input.val());
      value = isNaN(value) ? 0 : value;
      
      input.val(value + 1);
    });
  });
})(window.jQuery);

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div ng-app="example" ng-controller="ExampleController">
  <input type="number" id="input" ng-model="input" ng-change="change()" />
  <span>{{output}}</span>
  <button id="button">+</button>
</div>

Answer 4

The accepted answer which was triggering input event with jQuery didn't work for me. Creating an event and dispatching with native JavaScript did the trick.

$("input")[0].dispatchEvent(new Event("input", { bubbles: true }));

Answer 5

add .change() after setting the value.

example:('id').val.('value').change();

also don't forget to add onchange or ng-change tag in html

Answer 6

I don't think jQuery is required here.

You can use $watch and ng-click instead

<div ng-app="myApp">
  <div ng-controller="MyCtrl">
    <input test-change ng-model="foo" />
    <span>{{foo}}</span>

    <button ng-click=" foo= 'xxx' ">click me</button>
    <!-- this changes foo value, you can also call a function from your controller -->
  </div>
</div>

In your controller :

$scope.$watch('foo', function(newValue, oldValue) {
  console.log(newValue);
  console.log(oldValue);
});