If you're looking to achieve this, there are two ways to go about it. One option is to create a watch statement in the controller for the variable passed into the directives isolate scope.
// Code snippet for the view controller
$scope.sliderValue = 0;
$scope.$watch('sliderValue', function(newValue) {
if (angular.isDefined(newValue)) {
// Perform actions with the new slider value here
}
});
It's important to note that we use isDefined because every watch fires on scope compilation with the initial value being undefined.
The alternative approach involves enhancing your directive with a parameter that gets evaluated as the slider value changes (similar to a callback function).
// Example directive code
angular.module('my-ui-controles', []).directive('mySlider', [function() {
return {
template: '...',
scope: {
value: '=mySlider',
onChange: '&'
},
link: function(scope, elem, attrs) {
// Assume this function is triggered when the slider value changes
scope.changeValue = function(newValue) {
// Perform other internal tasks and notify external components
scope.onChange({value: newValue});
}
}
}
}])
Now, you can utilize this in your template like so:
<div my-slider="sliderValue" on-change="doStuff(value)"></div>
With this setup, whenever the slider value changes, we evaluate the onChange expression provided to the directive. The doStuff function will receive the new slider value. The object passed to onChange represents the scope used to evaluate the expression, allowing doStuff to be any method from your controller.
The key advantage here is that the logic for notifying others resides within the directive rather than implicitly within your controller through a watch statement.
I hope this helps steer you in the right direction.