AngularJS - ngClick, custom directive, and isolated scope issue - angularjs

Question

Consider the following directive: (Live Demo)
app.directive('spinner', function() {
return {
restrict: 'A',
scope: {
spinner: '=',
doIt: "&doIt"
},
link: function(scope, element, attrs) {
var spinnerButton = angular.element("<button class='btn disabled'><i class='icon-refresh icon-spin'></i> Doing...</button>");
element.after(spinnerButton);
scope.$watch('spinner', function(showSpinner) {
spinnerButton.toggle(showSpinner);
element.toggle(!showSpinner);
});
}
};
});
which is used like this:
<button ng-click="doIt()" spinner="spinIt">Spin It</button>
When spinner's value (i.e. the value of $scope.spinIt in this example) is true, the element should be hidden and spinnerButton should appear instead. When spinner's value is false, the element should be visible and spinnerButton should be hidden.
The problem here is that doIt() is not in the isolated scope, thus not called on click.
What would be the "Angular way" to implement this directive?

Answer 1

My suggestion is to look at what's going on with these spinners. Be a little more API focused.
Relevant part follows. We use a regular callback to indicate when we're done, so the spinner knows to reset the state of the button.
function SpinDemoCtrl($scope, $timeout, $q) {
$scope.spinIt = false;
$scope.longCycle = function(complete) {
$timeout(function() {
complete();
}, 3000);
};
$scope.shortCycle = function(complete) {
$timeout(function() {
complete();
}, 1000);
};
}
app.directive('spinnerClick', function() {
return {
restrict: 'A',
scope: {
spinnerClick: "=",
},
link: function(scope, element, attrs) {
var spinnerButton = angular.element("<button class='btn disabled'><i class='icon-refresh icon-spin'></i> Doing...</button>").hide();
element.after(spinnerButton);
element.click(function() {
spinnerButton.show();
element.hide();
scope.spinnerClick(function() {
spinnerButton.hide();
element.show();
});
});
}
};
});
Here's one that expects use of $q. It'll work better with Angular-style asynchronous operations, and eliminates the callback functions by instead having the spinner reset on fulfilment of the promise.

Answer 2

Here is the polished version of the directive I ended up with (based on Yuki's suggestion), in case it helps someone: (CoffeeScript)
app.directive 'spinnerClick', ->
restrict: 'A'
link: (scope, element, attrs) ->
originalHTML = element.html()
spinnerHTML = "<i class='icon-refresh icon-spin'></i> #{attrs.spinnerText}"
element.click ->
return if element.is('.disabled')
element.html(spinnerHTML).addClass('disabled')
scope.$apply(attrs.spinnerClick).then ->
element.html(originalHTML).removeClass('disabled')
Use it like so:
<button class="btn btn-primary" spinner-click="createNewTask()"
spinner-text="Creating...">
Create
</button>
Controller's code:
TasksNewCtrl = ($scope, $location, $q, Task) ->
$scope.createNewTask = ->
deferred = $q.defer()
Task.save $scope.task, ->
$location.path "/tasks"
, (error) ->
// Handle errors here and then:
deferred.resolve()
deferred.promise

Answer 3

Yes, it will call doIt in your isolated scope.
You can use $parent.doIt in that case
<button ng-click="$parent.doIt()" spinner="spinIt">Spin It</button>

Answer 4

From the AngularJS Documentation (http://docs.angularjs.org/guide/directive):
& or &attr - provides a way to execute an expression in the context of the parent scope. If no attr name is specified then the attribute name is assumed to be the same as the local name. Given and widget definition of scope: { localFn:'&myAttr' }, then isolate scope property localFn will point to a function wrapper for the count = count + value expression. Often it's desirable to pass data from the isolated scope via an expression and to the parent scope, this can be done by passing a map of local variable names and values into the expression wrapper fn. For example, if the expression is increment(amount) then we can specify the amount value by calling the localFn as localFn({amount: 22}).
so inlclude doIt: "&doIt" in your scope declaration, then you can use doIt as a function in your isolated scope.

Answer 5

I'm confused as to why you are not packaging up everything in the directive as if it's a self-contained module. That's at least what I would do. In other words, you have the click-handler in the HTML, some behavior in the directive and some behavior in the external controller. This makes your code much less portable and more decentralized.
Anyway, you may have reasons for this that are not shared, but my suggestion would be to put all the "Spin It" related stuff in the spinner directive. This means the click-handler, the doIt() function and template stuff all within the link function.
That way there's no need to worry about sharing scope and code entanglement. Or, am I just missing something?

Answer 6

I don't know about the 'angular' way of doing things, but i suggest not using an isolated scope but instead just creating a child scope. You then do attrs.$observe to get any properties you need for your directive.
I.E. :
app.directive('spinner', function() {
return {
restrict: 'A',
scope: true, //Create child scope not isolated scope
link: function(scope, element, attrs) {
var spinnerButton = angular.element("<button class='btn disabled'><i class='icon-refresh icon-spin'></i> Doing...</button>");
element.after(spinnerButton);
//Using attrs.$observe
attrs.$observe('spinner', function(showSpinner) {
spinnerButton.toggle(showSpinner);
element.toggle(!showSpinner);
});
}
};
});
I find this way is better than using '$parent' to escape the isolated scope in other directives (eg ngClick or ngModel) as the end user of your directive does not need to know whether or not using your directive requires them to use '$parent' or not on core angularjs directives.

Answer 7

Using CoffeeScript and a FontAwesome icon.
No need to manually specify the spinner-text
It will just add the spinner content left of the text while loading
We must use finally instead of then for the promise otherwise the spinner will stay there on failure?
I must use $compile because the contents of the button is dynamically compiled as I am using https://github.com/angular-translate/angular-translate
app.directive 'spinnerClick', ["$compile", ($compile) ->
restrict: 'A'
link: (scope, element, attrs) ->
originalHTML = element.html()
spinnerHTML = "<i class='fa fa-refresh fa-spin'></i> "
element.click ->
return if element.is('.disabled')
element.html(spinnerHTML + originalHTML).addClass('disabled')
$compile(element.contents())(scope)
scope.$apply(attrs.spinnerClick).finally ->
element.html(originalHTML).removeClass('disabled')
$compile(element.contents())(scope)
]