Call function from directive in $rootScope - AngularJS - javascript

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.

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.

Changing a model from a directive callback function in AngularJS has no effect

So, what I want is a custom directive which will read and clear the current selection, and then pass the selected text to a callback function. This works, but whatever I do in that callback function has no effect on the scope, which leads me to believe that there are multiple scopes, which are in conflict somehow.
First, I defined a directive like this:
angular.module('app').directive('onTextSelected', ['$window', function ($window) {
return {
restrict: 'A',
scope: {selectFn: '&'},
link: function (scope, element, attrs) {
$(element).mouseup(function () {
var selection = $window.getSelection().toString();
if ($window.getSelection().removeAllRanges) {
$window.getSelection().removeAllRanges();
} else if ($window.getSelection().empty) {
$window.getSelection().empty();
}
if (selection && selection.trim() !== "") {
scope.selectFn({
text: selection.trim()
});
}
});
}
};
}]);
It's used in the template as follows:
<pre ng-bind-html="message" id="messagePre" on-text-selected
select-fn="textSelected(text)"></pre>
And this is the callback function:
$scope.textSelected = function (text) {
console.log(text);
$scope.currentText = text;
};
I have a text box which uses $scope.textSelected as model, and setting it with the same code from another function works properly, but in this case it just doesn't. Nothing happens, although all the code gets executed (it prints on the console, for example).
It works after calling
$scope.$digest()
or using
$scope.$apply()
Probably related to the usage of jQuery here.

angular add function to $element in directive

I have a page with two directives. I need to invoke a function in one directive from the other. I have added the function to the $element object of the first directive and used jQuery to invoke it from the other. Is this the right approach or should I be using a context object shared by both directives?
//inside directive 1 link fn
$element[0].foo = function(){
console.log("test");
}
...
//inside directive 2 link fn
$('.className').foo()
The two directives are elements on a page with a shared controller. Each has an isolated scope. This seems to work well. Are there any reasons why I should not do this?
are the 2 directives sharing the same controller? If so, you could call a function on the controller from one directive which would "notify" the other. Or, you could use events, check this answer here
This is not the way you should do it. Try to avoid using $element, it does DOM manipulations which are slow and Angular takes care of by itself. To invoke a function in directiveB, triggered from directiveA, you better make a service.
angular.service('Communication', function () {
var _listeners = [];
return {
addListener: function (callback) {
_listeners.push(callback);
},
removeListener: function () {/* Clean up */},
invokeListeners: function (data) {
_listeners.forEach(function (listener) {
listener(data);
});
}
}
});
angular.directive('directiveB', ['Communication', function (Communication) {
return {
restrict: 'AE',
scope: {},
controller: directiveB
};
function directiveB (scope, element, attrs) {
Communication.addEventListener(function (data) { /* Do stuff with data */ });
}
}]);
angular.directive('directiveA', ['Communication', function (Communication) {
return {
restrict: 'AE',
scope: {},
controller: directiveA
};
function directiveA (scope, element, attrs) {
// trigger event in directive B
Communication.invokeListeners('test');
}
}]);

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");
}
};)

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