How to setup $emit in directive in my case - javascript

I am trying to use $emit in my code for a directive.
I have
(function () {
angular
.module('myApp')
.directive('testDirective', testDirective);
function testDirective() {
var directive = {
link: link,
restrict: 'A',
controller: testCtrl,
controllerAs: 'vm'
};
return directive;
function link(scope, element, attrs) {
}
}
function testCtrl() {
var vm = this;
// do something
vm.$emit('someEvent', {'id': '123'})
}
})();
However, I am getting 'TypeError: vm.$emit is not a function'. I am not sure how to fix this. Can anyone help? Thanks a lot!

controllerAs just means that scoped variables are attached directly to the controller -- it doesn't mean that the controller is an instance of an angular scope itself. In this case, you'll need to inject the scope into the controller and then emit the event from on the scope:
function testCtrl($scope) {
// do something
$scope.$emit('someEvent', {'id': '123'})
}
Also beware, the normal injection rules apply -- If you're going to minify this, you'll probably need something like:
testCtrl['$inject'] = ['$scope'];

Related

AngularJS Directive binding to controller

I'm trying to figure out AngularJS directives. I've got the following JSFiddle with an example of something I'm trying to do. https://jsfiddle.net/7smor9o4/
As you can see in the example, I expect the vm.alsoId variable to be equal to vm.theId. In the template vm.theId displays the correct value but vm.alsoId does not.
What am I doing wrong? How could I accomplish my goal.
If it helps the final idea is to execute something as the following:
function directive(service) {
var vm = this;
vm.entity = null;
init();
function init() {
service.getEntity(vm.theId).then(function (entity) {
vm.entity = entity;
});
}
}
As you've noticed, the bindToController bindings are not immediately available in the controller's constructor function (unlike $scope, which are). What you're looking for is a feature introduced with Angular 1.5: Lifecycle Hooks, and specifically $onInit.
You had the right idea; simply replace your init function definition and invocation as follows:
vm.$onInit = function () {
service.getEntity(vm.theId).then(function (entity) {
vm.entity = entity;
});
};
And here is your updated fiddle.
(Alternatively, without this solution, you'd have needed a watch.)
Angular recommends that you bind a controller "only when you want to expose an API to other directives. Otherwise use link."
Here's a working fiddle using the link function.
angular.module('app', [])
.directive('directive', directive);
angular.element(function() {
angular.bootstrap(document, ['app']);
});
function directive() {
return {
restrict: 'E',
scope: {
theId: '<'
},
template: `
alsoId: <span ng-bind="alsoId"></span>
theId: <span ng-bind="theId"></span>`,
link: link
};
}
function link(scope, element, attrs) {
init();
function init() {
scope.alsoId = scope.theId;
}
}

Angular directive: whats the difference between scope in controller vs scope in link function?

Im learning about Angular directives and I can't wrap my head around the scope topic. Suppose I have this custom directive which is named parentDirective. It has a controller property and a link property, as follows:
angular.module("app").directive("parentDirective", function () {
return {
restrict: "E",
templateUrl: "dirs/parent.html",
scope:{
character: "="
},
controller: function ($scope) {
$scope.getData = function (data) {
console.log(data);
}
},
link: function (scope,elem, attrs) {
elem.bind("click", function (e) {
//get object here?
});
scope.getData = function (data) {
console.log(data);
}
}
}
});
Its template is defined as follows:
<p ng-click="getData(character)">
{{character.name}}
</p>
I can get the character object in the controller function through the $scope variable and I have access to the same data in the link function through scope. Whats the difference between the two methods in this regard? Second question, Is it possible to bind a click to the directive and get the object like this:
elem.bind("click", function (e) {
//get object here?
});
Scope is specific to current directive instance and is the same object in both functions.
For defining methods on the scope, there's no difference if they are defined in controller or link function, unless there is race condition that requires the method to be defined as early as possible. For this reason it makes sense to define scope methods in controller.
Event handler doesn't differ from any other function, it is
elem.on("click", function (e) {
scope.$apply(function () {
scope.character...
});
});
scope.$apply(...) wrapper doesn't hurt anyway, but the necessity of it depends on what happens with scope.character.
The directive can have only controller and no link. Current Angular versions (1.5+) suggest the style where bindToController + controllerAs are used instead of scope bindings as common ground for directives and components.
Then the directive may look like
restrict: "E",
template: '<p>{{$ctrl.character.name}}</p>',
controllerAs: '$ctrl',
bindToController: { character: "=" },
controller: function ($element, $scope) {
var self = this;
self.getData = function (data) { ... };
$element.on("click", function (e) {
scope.$apply(function () {
self.character...
});
});
}
link function may appear as $postLink controller hook, but here it is not needed.

Angular Directive Controller best practice

Which one is the best way to define directive controller. I referred some site they explained Option1.
Option 1:
angular.module('app')directive('AppHeader', AppHeader);
function AppHeader() {
var headerDirective = {
restrict: 'E',
templateUrl: 'header.html',
link: linkFunc,
controllerAs: 'vm',
controller: NavCtrl
};
return headerDirective;
function linkFunc(scope, element, attrs) {
/* */
}
}
NavCtrl.$inject = ['$scope', 'Service'];
function NavCtrl($scope, Service) {
var vm = this;
/* Controller actions */
}
In the above code Controller separated from the directive function block.
Option 2:
angular.module('app').directive('AppHeader', AppHeader);
function AppHeader()
{
var headerDirective = {
restrict: 'E',
templateUrl: 'header.html',
link: linkFunc,
controllerAs: 'vm',
controller: NavCtrl
};
return headerDirective;
function linkFunc(scope, element, attrs) {
/* */
}
NavCtrl.$inject = ['$scope', 'Service'];
function NavCtrl($scope, Service) {
var vm = this;
/* Controller actions */
}
}
In the above code Controller added in directive function block.
So which one is best practice to create and define the Directive controller and Why. Thanks in advance.
With regards to Option 2, you have scoped the function to level where you are actually using.
In Option 1, you have scoped the function a level higher, There is no need for it to be a level above as it will not be reused.
I feel Option 2 makes the function correctly scoped.
Further you might want to enclose entire Option 2 code in IIFE (immediately invoked function expression)
(function(){
//Your code here
})();
You should go with option 1 because.
The directive's controller should be outside the directive's closure. This way you eliminate possible issues where the injection gets created as unreachable code after a return.
You should read John Papa's style guide, he explains all kind of things about code styling in angular.

Sharing scope between Directives - missing $http

Here are mine two directives. I basically want to share the scope between them. However with this I get an undefined $http error. I know I need to put $http somewhere, but where?
aresAnalytics.directive('market', function($http) {
return {
restrict: 'E',
controller: function ($scope, Data) {
$scope.data = Data;
},
link: function(scope, element, attrs) {
element.bind('click', function() {
console.log("A1 " + attrs.market);
scope.temp = attrs.market;
$http.get('get_markets').success(function(markets) {
Data.markets = markets;
});
})
}
}
});
aresAnalytics.directive('events', function($http) {
return {
restrict: 'E',
controller: function ($scope) {
scope = $scope;
},
link: function(scope, element) {
element.bind('click', function() {
console.log(scope.temp);
});
}
}
});
HTML:
<market ng-repeat="market in data.markets" market="{{ market }}">
{{ market }}
</market>
Also, I think the way I am doing this
$http.get('get_markets').success(function(markets) {
Data.markets = markets;
});
is not correct, what can I replace with it.
And, should I use Isolate Scope '#' instead? How will that look like?
Thanks for reading this!
You need to inject the $http service like so.
app.directive('something', function( $http ) { ... });
Angular Dependency Injection
To access attributes like that there are many ways, but this is a simple way.
change html to
<market ng-repeat="market in data.markets" market="market">
{{ market }}
</market>
Require parse like this
app.directive('something', function( $http, $parse ) { ... });
And get your attribute like so
scope.temp = $parse(attrs.market)(scope);
This way you're getting it directly from the scope while the other way, angular hasn't rendered the attribute yet.
The problem is with your dependency injection. Try this:
aresAnalytics.directive('market', ['$http', function($http) {
// (you code)
}]);
or if you don't use code minifiers/uglifiers:
aresAnalytics.directive('market', function($http) {
// (you code)
});
I don't know, but I simply had to append a $parent to my scope to always use the parent scope. (like use scope.$parent instead of scope).
REF: https://github.com/angular/angular.js/wiki/Understanding-Scopes

Modify template in directive (dynamically adding another directive)

Problem
Dynamically add the ng-bind attribute through a custom directive to be able to use ng-bind, ng-bind-html or ng-bind-html-unsafe in a custom directive with out manually adding to the template definition everywhere.
Example
http://jsfiddle.net/nstuart/hUxp7/2/
Broken Directive
angular.module('app').directive('bindTest', [
'$compile',
function ($compile) {
return {
restrict: 'A',
scope: true,
compile: function (tElem, tAttrs) {
if (!tElem.attr('ng-bind')) {
tElem.attr('ng-bind', 'content');
$compile(tElem)
}
return function (scope, elem, attrs) {
console.log('Linking...');
scope.content = "Content!";
};
}
};
}]);
Solution
No idea. Really I can not figure out why something like the above fiddle doesn't work. Tried it with and with out the extra $compile in there.
Workaround
I can work around it might adding a template value in the directive, but that wraps the content in an extra div, and I would like to be able to that if possible. (See fiddle)
Second Workaround
See the fiddle here: http://jsfiddle.net/nstuart/hUxp7/4/ (as suggested by Dr. Ikarus below). I'm considering this a workaround for right now, because it still feels like you should be able to modify the template before you get to the linking function and the changes should be found/applied.
You could do the compiling part inside the linking function, like this:
angular.module('app').directive('bindTest', ['$compile', function ($compile) {
return {
restrict: 'A',
scope: true,
link: {
post: function(scope, element, attrs){
if (!element.attr('ng-bind')) {
element.attr('ng-bind', 'content');
var compiledElement = $compile(element)(scope);
}
console.log('Linking...');
scope.content = "Content!";
}
}
};
}]);
Let me know how well this worked for you http://jsfiddle.net/bPCFj/
This way seems more elegant (no dependency with $compile) and appropriate to your case :
angular.module('app').directive('myCustomDirective', function () {
return {
restrict: 'A',
scope: {},
template: function(tElem, tAttrs) {
return tAttrs['ng-bind'];
},
link: function (scope, elem) {
scope.content = "Happy!";
}
};
});
jsFiddle : http://jsfiddle.net/hUxp7/8/
From Angular directive documentation :
You can specify template as a string representing the template or as a function which takes two arguments tElement and tAttrs (described in the compile function api below) and returns a string value representing the template.
The source code tells all! Check out the compileNodes() function and its use of collectDirectives().
First, collectDirectives finds all the directives on a single node. After we've collected all the directives on that node, then the directives are applied to the node.
So when your compile function on the bindTest directive executes, the running $compile() is past the point of collecting the directives to compile.
The extra call to $compile in your bindTest directive won't work because you are not linking the directive to the $scope. You don't have access to the $scope in the compile function, but you can use the same strategy in a link function where you do have access to the $scope
You guys were so close.
function MyDirective($compile) {
function compileMyDirective(tElement) {
tElement.attr('ng-bind', 'someScopeProp');
return postLinkMyDirective;
}
function postLinkMyDirective(iScope, iElement, iAttrs) {
if (!('ngBind' in iAttrs)) {
// Before $compile is run below, `ng-bind` is just a DOM attribute
// and thus is not in iAttrs yet.
$compile(iElement)(iScope);
}
}
var defObj = {
compile: compileMyDirective,
scope: {
someScopeProp: '=myDirective'
}
};
return defObj;
}
The result will be:
<ANY my-directive="'hello'" ng-bind="someScopeProp">hello</ANY>

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