I have been working with isolated scope directives for a little time and a question came in mind watching it's behavior:
Why can't i bind variables that i define inside the directive inherited scope directly to the view?
Let me show an example on this code pen:
http://codepen.io/anon/pen/VLKjrv
When i create a new $scope variable inside the directive controller and i try to bind it on the view, it does not works.
By the other hand, when i bind that variable on a html that comes from the template directive attribute, it does works.
Check out the code:
<body ng-app="isolated-test-app">
<section ng-controller="isolatedTestCtrl">
<article>
<h1>test1</h1>
<div isolated-directive binding-from-attr="test">
<span ng-bind="test"></span>
<span ng-bind="test2"></span>
</div>
<h1>test2</h1>
<div isolated-directive-number-two binding-from-attr="test">
</div>
</article>
</section>
angular.module('isolated-test-app', [])
.controller('isolatedTestCtrl', function isolatedTestCtrl($scope){
$scope.test = 'Binded from parent controller';
})
.directive('isolatedDirective', function isolatedDirective(){
var directive = {
scope: {
bindingFromAttr: '=',
},
controller: function directiveController($scope){
$scope.test2 = 'Binded from directive controller!';
},
};
return directive;
})
.directive('isolatedDirectiveNumberTwo', function isolatedDirective2(){
var directive = {
scope: {
bindingFromAttr: '=',
},
template:'<span ng-bind="bindingFromAttr"></span>\
<span ng-bind="test2"></span>',
controller: function directiveController($scope){
$scope.test2 = 'Binded from directive controller!';
},
};
return directive;
})
test1
Binded from parent controller
test2
Binded from parent controller
Binded from directive controller!
I was expecting the result of test2 on test1.
Why does that happens?
There is a difference between directive template and the directive's element's contents with regards to what scope applies.
In isolate scope (scope: {}) directives, the isolate scope applies to the template, but not to the contents. The contents have the same scope as the directive's parent. Also, note, that the contents would be replaced by the template, if the template is defined. To use the contents in addition to the template requires "transcluding" (transclude: true) (this is, however, outside of scope for this answer).
If you are confused, you could always check $scope.$id to see which scope applies:
<div>parent scope: {{$id}} (will be 2)</div>
<isolate-scope>
contents of isolate scope directive: {{$id}} (will also be 2)
</isolate-scope>
<isolate-scope-with-template>
contents will be replaced with the template
</isolate-scope-with-template>
.directive("isolateScopeWithTemplate", function(){
return {
scope: {},
template: "template: {{$id}} (will NOT be 2)"
}
})
(of course, the actual $id could be different)
In child scope (scope: true) directives, the scope that applies to the content is actually the same that would have applied to the template (same here - the template would replace the contents if it exists, unless you transclude).
Now, to answer your question:
The first <span ng-bind="test2"></span> binds to a non-existent $scope.test2 in the parent scope and so it is empty.
But the <span ng-bind="test2"></span> in the template of isolatedDirectiveNumberTwo binds to the isolate scope of that directive, which defines $scope.test2 = 'Binded from directive controller!'.
This is my guess base on experiment in http://codepen.io/anon/pen/MwjjBw
so for test 1, the directive scope doesnt have test/test2 since the dom object is belong to controller. Hence in order to update it you have to use
$scope.$parent.test2 = "" ;
and for test 2, as the template is created as part of directive hence the dom object is belong to directive and also accessible by controller ( I guess $compile adding this into controller scope/watch).
You can also see that test1 doesnt have any watcher as there is no binding happen.
Now i get the whole picture, as New Dev's answer stated on his answer
In isolate scope (scope: {}) directives, the isolate scope applies to the template, but not to the contents. The contents have the same scope as the directive's parent.
So i have learned that there is a difference between directive contents and template and how the scope is inherited on isolated scopes.
For my application setting the scope to true solved entirely my problem.
Also, kwan245's solution is a real good work-around of this issue.
Both answers cleared my mind, many thanks to New Dev and kwan245 :)
Related
I would like to create a directive that has transcluded content that the directive can bind to and modify. The directive has an isolate scope. I imagine it working something like this:
<my-directive bound-item-name="childObj">
<input ng-model="childObj.someField">
</my-directive>
At runtime, I want to use childObj as an alias for an object on my-directive's isolate scope called activeObject. Essentially, you might think of this as similar to the way ng-repeat lets you use a statment like obj as alias in objList and in the transcluded content alias refers to the individual instance.
I can't seem to figure out how I can actually do this... if I change the transluded content to refer to $parent.activeItem it does work the way I intended, but I feel like that's expecting the transcluded content to know too much about how the directive works. It seems like modifying in the compile function might work, except I can't see, in the docs, how I can actually do that with the transcluded content. Forcing the transcluded content to share its scope with the directive would be OK, although I see no evidence that there's some way to do that.
This must be possible, but how?
Fiddling around with this some more, I am able to get it to work by modifying scope.$$childHead[scope.boundItemName] instead of using scope.activeObject in the directive. While this works I'd like to not rely on undocumented internal objects, if possible.
The link function of the directive is given the transclude function as the 5th parameter.
link: function(scope, element, attrs, ctrls, transclude){
// ...
}
This transclude function takes a scope variable that you can create and another function - called "clone linking function" - that places the pre-linked transcluded content in the DOM. The transclude function links against that scope variable that you provided.
Here's how it works.
transclude: true,
scope: {}, // you are free to use whatever scope you need
link: function(scope, element, attrs, ctrls, transclude){
var boundObj = {}; // your object
var alias = attrs.boundItemName;
// let's create an isolate scope for the transcluded content
var newScope = scope.$new(true);
newScope[alias] = boundObj;
transclude(newScope, function(preLinkContent){
element.append(preLinkContent);
});
}
Then, if you used your example:
<my-directive bound-item-name="foo">
<input ng-model="foo.text">
</my-directive>
Then, the transcluded ng-model would write into your internal boundObj's .text property.
Demo
I have two simple directives who generate similar elements in the DOM.
Both have an isolated scope
Both have an ng-click to a metod that displays a message.
One has the ng-click declared in the html file and that one triggers the method in the containing scope.
The other has the ng-click in the directive template and a click triggers the method in the isolated scope
Why doesn't both trigger the method in the isolated scope?
Here is a Plunk
Javascript
var app = angular.module('plunker', []);
app.controller('MainCtrl', function($scope) {
$scope.name = 'World';
$scope.alertMessage = function(){
alert('I live in mainController');
}
});
app.directive('isolated', function(){
return {
scope: {},
link: function(scope, element, attrs) {
scope.alertMessage = function(){
alert('I live in the isolated directive');
};
}
};
});
app.directive('isolatedWithTemplate', function(){
return {
scope: {},
replace: true,
template: '<button ng-click="alertMessage()">Press me</button>',
link: function(scope, element, attrs) {
scope.alertMessage = function(){
alert('I live in the isolated directive');
};
}
};
});
Html
<button isolated ng-click="alertMessage()">Press me</button>
<div isolated-with-template></div>
(Answer updated with corrections more info as pointed out by #Edminsson)
Refer to following link to understand the scopes - although the link does not explain the above behavior my answer will try to do explain.
Understanding Scopes
Following will try to explain why the element with 'isolated' directive says 'I am in mainController scope' instead of 'I am in isolated scope.
Note the order of the two DOM element does not matter, neither the priority affects anything with respect to what we saw.
<div isolated-with-template></div>
<button isolated ng-click="alertMessage()">No Template</button>
Each directive on the element is compiled on the scope of the parent.
That means the ng-click got bound to the scope function in the MainController. The isolate directive does create a new isolated scope and the function on it but the ng-click is already bound to the function object $scope.alertMessage() from mainController.
Element with isolated-with-template is also getting compiled with the parent scope. However when it encounters the directive it has now a template. This gets compiled (to be precise nodeLinkFn. There is afterTemplateNodeLinkFn so directives with templates or templateUrls will use this). At this time the isolated scope has the function alertMessage from the isolated scope. Also know that the MainController's alertMessage was already defined on that scope prior to all this.
1) Angular processes the DOM depth first and links backwards
2) root of the template gets its immediate scope
3) when multiple directives are requesting scopes on an element you get only one scope
What happens with scope = true ?
In this plnkr you will notice that the directive no longer says 'I am in mainController'.
scope:true,
You are actually getting brand new child scope. When a linking function is created angular knows about this scope being a brand new scope.
One trick for isolated scopes
Try assigning template: ' ', and replace: true
and you have your isolated scope in action.
Isolated scope trick using another example
.directive("client", function() {
return {
restrict: "A",
template: ' ',//notice extra spaces
replace: true,//notice this
scope: {
name: "#name",
client: "=client"
}
};
});
<button isolated ng-click="alertMessage()">Press me</button>
in this case the ng-click is independent of isolated directive, it will work even if you change html to
<button ng-click="alertMessage()">Press me</button>
so the ng-click above is not working on isolate directive but on scope of your controller...
the ng-click of isolated-with-template is working in scope of a directive..
I have an Angular directive which permit to render an user, and create a link to view the user profile, declared as:
.directive('foafPerson', function() {
return {
restrict: 'E',
templateUrl: 'templates/person.html',
scope: {
personModel: '=',
onClickBindTo: '=',
onPersonClick: '&'
}
};
As you can see, I'm trying 2 solutions to be able to visit and load the full user profile: onClickBindTo and onPersonClick
I use it like that to render a list of persons + their friends:
// display the current user
<foaf-person person-model="person" on-person-click="changeCurrentProfileUri(person.uri)" on-click-bind-to="currentProfileUri"></foaf-person>
// display his friends
<div class="profileRelationship" ng-repeat="relationship in relationships">
<foaf-person person-model="relationship" on-person-click="changeCurrentProfileUri(relationship.uri)" on-click-bind-to="currentProfileUri"></foaf-person>
</div>
On the template, I have a link that is supposed to change an attribute of the controller (called currentProfileUri)
<a href="" ng-click="onClickBindTo = personModel.uri">
{{personModel.name}}
<a/>
I can see that the controller scope variable currentProfileUri is available in the personTemplate.html because I added a debug input: <input type="text" ng-model="onClickBindTo"/>
Unfortunately, when I modify the input value, or when I click on the link, the currentProfileUri of the controller is not updated. Is this normal or am I missing something?
With the other method it seems to work fine:
<a href="" ng-click="onPersonClick()">
{{personModel.name}}
<a/>
So to modify a model of the parent scope, do we need to use parent scope functions?
By the way, passing an expression with &, I tried another solution: not using a function declared in the controller scope:
<foaf-person person-model="relationship" on-person-click="currentProfileUri = relationship.uri"></foaf-person>
How comes it does not work?
My controller has nothing really fancy:
$scope.currentProfileUri = 'https://my-profile.eu/people/deiu/card#me';
$scope.$watch('currentProfileUri', function() {
console.debug("currentProfileUri changed to "+$scope.currentProfileUri);
loadFullProfile($scope.currentProfileUri);
})
$scope.changeCurrentProfileUri = function changeCurrentProfileUri(uri) {
console.debug("Change current profile uri called with " + uri);
$scope.currentProfileUri = uri;
}
I am new to Angular and read everywhere that using an isolate scope permits a two-way data binding with the parent scope, so I don't understand why my changes are not propagated to the parent scope and my debug statement doesn't fire unless I use the scope function changeCurrentProfileUri
Can someone explain me how it works?
In your example the scopes hierarchy is the following:
controller scope
ng-repeat scope
foaf-person scope
so when you declare two-way binding for 'currentProfileUri' it is actually bound to the scope created by ng-repeat, not by the controller, and when your code changes value of onClickBindTo then angularjs executes 'currentProfileUri = newValue' in the ng-repeat scope.
Solution is to use objects instead of primitive values for two-way bindings - in this case scopes inheritance always work in proper way. I mean something like that:
// display the current user
<foaf-person person-model="person" on-click-bind-to="currentProfile.uri"></foaf-person>
// display his friends
<div class="profileRelationship" ng-repeat="relationship in relationships">
<foaf-person person-model="relationship" on-click-bind-to="currentProfile.uri"></foaf-person>
</div>
I've prepared a js-fiddle which illustrates this behavior
Well, since 'improve this doc' button on AngularJS documentation site doesn't work and discussion is now closed, I'd like to ask a question about 'isolated scope pitfall' paragraph of ngModelController.
<div ng-app="badIsolatedDirective">
<input ng-model="someModel"/>
<div isolate ng-model="someModel"></div>
<div isolate ng-model="$parent.someModel"></div>
</div>
angular.module('badIsolatedDirective', [])
.directive('isolate', function() {
return {
require: 'ngModel',
scope: { },
template: '<input ng-model="innerModel">',
link: function(scope, element, attrs, ngModel) {
scope.$watch('innerModel', function(value) {
console.log(value);
ngModel.$setViewValue(value);
});
}
};
});
I expected to see the third input affecting first one (cause we just isolated second input's scope and have no reference to 'someModel' scope value), btw behavior of this example is just stunning: second input affects first, third doesn't affect anything. So the question is: am I loosing the concept or just don't understand it, or there are mistakes (maybe, not mistakes, but just no connection to the topic) in the example code (well, I changed it on Plunkr to make it work as I expected).
In 1.2.0 timely-delivery there was a major change (here) to how multiple isolate scope directives on the same element work. This change apparently hasn't been reflected in their documentation.
Prior to 1.2.0 all directives on an element shared an isolate scope if any of the directives requested an isolate scope. Therefore in the above example the ngModel directive shared the isolate directive's scope. Which is why we had to reference the parent scope like this- ng-model="$parent.someModel"
That is no longer true in 1.2.0.
In 1.2.0 and beyond the ngModel directive no longer shares scope with isolate. ngModel is now on the parent scope of the isolate directive. Thus we now need ng-model="someModel" instead of ng-model="$parent.someModel"
Here's their description of the change (keeping in mind as you read this that ngModel is a directive):
Make isolate scope truly isolate
Fixes issue with isolate scope leaking all over the place into other directives
on the same element.
Isolate scope is now available only to the isolate directive that requested it
and its template.
A non-isolate directive should not get the isolate scope of an isolate directive
on the same element,instead they will receive the original scope (which is the
parent scope of the newly created isolate scope).
BREAKING CHANGE: Directives without isolate scope do not get the
isolate scope from an isolate directive on the same element. If your
code depends on this behavior (non-isolate directive needs to access
state from within the isolate scope), change the isolate directive to
use scope locals to pass these explicitly.
Before
<input ng-model="$parent.value" ng-isolate>
.directive('ngIsolate', function() { return {
scope: {},
template: '{{value}}' }; });
After
<input ng-model="value" ng-isolate>
.directive('ngIsolate', function() { return {
scope: {value: '=ngModel'},
template: '{{value}} }; });
Here's a version running 1.2.0-rc3 (the last version before this change) which operates like their documentation describes: http://jsfiddle.net/5mKU3/
And immediately after, 1.2.0 stable, we no longer need, or want, the reference to '$parent': http://jsfiddle.net/5mKU3/1/
I am trying to build generic code as much as possible.
So I'm having 2 directives, one nested inside the other while I want the nested directive to call a method on the main controller $scope.
But instead it requests the method on the parent directive, I want to know how to execute a method against the main controller scope instead of the parent directive.
Here is a sample code for my issue
My HTML should look something like this:
<div ng-controller='mainctrl'>
<div validator>
<div datepicker select-event='datepickerSelected()'/>
</div>
</div>
Javascript:
var app = angular.module("app",[]);
var mainctrl = function($scope){
$scope.datepickerSelected = function(){
//I WANT TO ACCESS THIS METHOD
}
}
app.directive("validator",function(){
return {
scope : {
//the datepicker directive requests a datepickerSelected() method on this scope
//while I want it to access the mainctrl scope
}
link: function(scope){
//some code
}
}
});
app.directive("datepicker", function(){
return{
scope: {
selectEvent: '&'
}
link: function(scope, elem){
//example code
$(elem).click(scope.selectEvent); //want this to access mainctrl instead validator directive
}
}
});
Simply remove the validator directive's scope property, thus eliminating its isolated scope. That means that validator will have the same scope that it is nested in (your controller) and datepicker will use that scope.
Another option if you want both to have isolated scopes (doesn't sound like you do) is to pass the function through to "validator's" scope.