AngularJS Directive binding to controller - javascript

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;
}
}

Related

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.

call a global function in directives in ng

i have a function which i call more than once ( in different directives).
So is there a way to call a function in every directive?
One solution would be to make the function as a service.
But the service does need a return value, doesn´t it?
this.changeDesign = function (currentstep) {
//do something
};
this method I call many times.
You should consider to avoid using global variables or put something on the global scope. Maybe it works now, but if your project gets bigger, you will probably get a lot of problems. More infos for example: https://gist.github.com/hallettj/64478
Here is an example, how you can use a factory, which you can inject into your directives (coding style inspired by John Papa https://github.com/johnpapa/angular-styleguide#factories):
(function () {
"use strict";
angular.module('my-app').provider('MyFactory', MyFactory);
MyFactory.$inject = [];
function MyFactory() {
var service = {
changeDesign: myChangeDesignImpl
};
function myChangeDesignImpl() { }
this.$get = function() {
return service ;
};
}
})();
You can now inject your service into a directive like this:
(function () {
"use strict";
angular.module('my-app').directive('MyDirective', MyDirective);
MyDirective.$inject = ["MyFactory"];
function MyDirective(MyFactory) {
var directive = {
restrict: 'E',
template: "/template.html",
link: link
};
return directive;
function link(scope, el, attr) {
MyFactory.changeDesign();
}
}
})();
you can do it in a directive that you will delcare on your elements.
angular.module('myDesignModule', [])
.directive('myDesignDirective', function() {
return {
link: function(scope, element, attrs, ctrl){
element.addClass("myClass");
}
};)

What is angularjs $compile double parenthesis

I 'm a bit worried If I am asking a noob question or if it is a javascript feature that I haven't been able to locate despite plenty of googling
I am adding a simple directive programmatically using $compile and all is working fine.
My question is this line
var el = $compile(newElement)($scope);
How do the double parenthesis work/ what do they do? Complete code below for reference but its just the parenthesis which I am not sure about.
var myApp = angular.module('myApp', []);
myApp.directive('myDirective', function() {
return {
template: 'Hello',
restrict: 'E'
}
});
myApp.controller('mainController', [
'$scope', '$compile', function($scope, $compile) {
$scope.addDirective = function() {
var newElement = angular.element(document.createElement('my-directive'));
var el = $compile(newElement)($scope);
angular.element(document.body).append(el);
};
}
]);
$compile returns another function. You can do something similarly:
function foo(greeting) {
return function(target) { console.log(greeting, target) };
}
foo('Hello, ')('world');
As you already know that parenthesis in javascript is an function invocation operator (and also grouping). In other words, with () operator you call a function. From here it is clear that the code
$compile(newElement)($scope);
means that result of $compile(newElement) is a function, so it can be executed. This returned function accepts one parameter - a scope object in which context new DOM element should be compiled.
$compile(tElement, tAttrs, transclude) returns the Directive link: (post-link) function.
app.directive('exampleDirective', [function () {
return {
restrict: 'A',
scope: { value: '=value'},
template: template,
link: function (scope, element, attr) {
scope.count = 0;
scope.increment = function() {
scope.value++;
};
}
};
}]);
In this case, $compile('<div example-directive></div>'); will return the link: function so you can call it with arguments (scope as first) and instanciate the context.
It's all just standard Javascript syntax for calling functions. What might be confusing is that $compile is a function that returns a function. So
$compile(newElement)
is itself function, and can be called like any other function, which is what's happening when writing
$compile(newElement)($scope);
You can break this up into separate lines if you wish, which might make it clearer:
var linkFunction = $compile(newElement);
linkFunction($scope);
You can refer to the usage of $compile in the docs.
As a side-note, I would be wary of using $compile directly: you might be overcomplicating things, and there could be simpler alternatives (it has been very rare that I've ever had to use it).

Call function from directive in $rootScope - AngularJS

What I want to do:
I'm trying to create a function within a directive that can be called from the $rootScope.
The Problem:
It seems to only be working on the last item in the DOM which has this directive. I'm guessing that what's happening is rootScope.myFunction gets overwritten each time this directive runs.
The Question:
How can I create one function in the $rootScope which, when called, runs the internal function for each directive instead of just the last one?
The Relevant Code:
(function() {
angular.module('home')
.directive('closeBar', closeBar);
closeBar.$inject = ['$rootScope', '$window'];
function closeBar(rootScope, window) {
return {
scope: true,
restrict: 'A',
link: function(scope, element, attrs) {
var myFunction = function() {
// do stuff
};
myFunction();
rootScope.myFunction = function() {
myFunction();
};
}
};
}
})();
Then in a different script, I want to call:
rootScope.myFunction();
Note, I'm not allowed to share actual code from the project I'm working on so this is a more general question not tied to a specific use case.
A simple solution would be to create a special function in your rootScope that accepts functions as an argument, and pushes it into an array, and you will be able to invoke that function later which will call all the registered functions.
angular.module('myApp').run(['$rootScope', function($root) {
var functionsToCall = [];
$root.registerDirectiveFunction = function(fn, context) {
context = context || window;
functionsToCall.push({fn: fn, context: context});
}
$root.myFunction = function(args) {
functionsToCall.forEach(function(fnObj) {
fnObj.fn.apply(fnObj.context,args);
});
}
}
And in your directive:
link: function($scope, $el, $attr) {
function myFunct() {
}
$scope.$root.registerDirectiveFunction(myFunct, $scope);
//call it if you want
$scope.$root.myFunction();
}
This should cover your scenario.

Call Controller Method From Scope Angular Js

JQuery to Directive
I want to call a method from the scope of this directive but can't seem to work it out (if possible).
$("my-directive").first().scope().loadData();
Directive Looks Something Like This
I would like to call the loadData function from the directive code below.
app.directive("myDirective", function () {
return {
restrict: "E",
templateUrl: "..."
scope: {},
controller: function ($scope, $element, $attrs) {
var self = this;
$scope.loadData = function () {
...
};
}
};
});
Scope is accessible inside the directive
You can get any child of the element of which directive is applied and get scope of it.
$('my-directive').first().children(":first").scope().loadData()
Strajk's answer is correct!
When Code is Added Dynamically setTimeout Needed
In the following example detail row has a nested directive (random-testees). I get the scope from that to dynamically compile the directive (dynamic and late-bound). The setTimeout is needed because it seems to take a bit before the
var detailRow = e.detailRow;
// Compile the directive for dyanmic content.
angular.element(document).injector().invoke(function ($compile) {
var scope = angular.element(detailRow).scope();
$compile(detailRow)(scope);
});
// Get some data from directive.
var testId = detailRow.find("random-testees").attr("testid");
// Wait, and call method on the directive.
setTimeout(function () {
var randomTesteesScope = $("random-testees").first().children(":first").scope();
randomTesteesScope.loadTestees(this);
}.bind(testId),200);
Not Very Confident About This
This seems a little brittle since I was getting mixed results with a 100 ms timeout sometimes and error when the randomTesteesScope returned undefined.

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