Why does the angular expression in the directive template execute twice? - angularjs

Its a simple directive:
app.directive('ngFoo', function($parse){
var controller = ['$scope', function ngNestCtrl($scope) {
$scope.getCanShow = function() {
console.log('show');
return true;
};
}];
var fnPostLink = function(scope, element, attrs) {
console.log('postlink');
};
var fnPreLink = function(scope, element, attrs) {
console.log('prelink');
};
var api = {
template: '<div ng-if="getCanShow()">foo</div>',
link: {
post: fnPostLink,
pre: fnPreLink
},
restrict: 'E',
controller:controller
};
return api;
});
My goal was to find when "show" gets output to console. At this moment I figure it happens after linking (pre & post).
This makes sense. Since the template is rendered after those phases. (Correct me if I am wrong).
But then again, why would the template be rendered twice?
http://plnkr.co/edit/JNhON2lY9El00dzdL39J?p=preview

Angular has multiple digest cycles and you're seeing two of them. This is totally normal and perfectly ok.

Related

Angular Directive not working when DOM updated

I have following directive
var app = angular.module('TestApp', []);
app.directive('selectMultiple', function() {
return {
restrict: 'A',
link: function(scope, element, attrs) {
$(element).find('select').material_select();
$(element).find("ul li").first().click(function() {
$(element).find("ul li:not(:first-child)").each(function(index) {
$(this).find("input[type=checkbox]").prop("checked", $(element).find("ul li").first().find("input[type=checkbox]").prop("checked"));
});
});
}
};
});
And I am also using dirpagination on same page, Its working , but when page changed, means DOM gets new elements, whatever written in directive is completely not working.
AM I missing any thing, I am new to angular so might be I'll be missing some things
Thanks

Typeerror - Not a function in angular directive

I have defined a custom click directive as below:
(function() {
'use strict';
angular.module('myApp.core')
.directive('customClick', customClick);
customClick.$inject = ['$rootScope'];
function customClick() {
return {
restrict: 'A',
/*scope: {
customClick: '&'
},*/
link: function(scope, element, attrs){
$(element).on('click', function(e) {
scope.$apply(function() {
console.log("Hello..customClick..");
scope.customClick();
});
});
}
};
}
})();
And I get the following error on this;
Error logged by WDPR Angular Error handler service {xx.."stacktrace":"TypeError: a.customClick is not a function","cause":"unknown cause"}(anonymous function)bowerComponents.js:5745
How can I resolve this? If I add scope with '&' I get demanding isolated scope. Hence how to resolve it?
If I remove - scope.customClick();, it does not show anything on second html for custom-click, it has impact on only 1 html, and its controller. I want to use it in multiple controller + html.
customClick is a function on the directive itself. It is not a function on the scope. That's why the error has occurred.
link is used to manipulate dom/add event handlers on elements, which you have rightly done with element.bind('click', function() {
Whenever click occurs, the function binded to click automatically gets invoked. There is no need of watch and the invoking statement.
Your link can just be
link: function(scope, element){
element.bind('click', function() {
console.log("Hello..customClick..");
});
}
As you have used camel case in naming the directive, exercise caution in its usage in template.
You can use it as <p custom-click>hi</p>
I would recommend you to avoid using jQuery in angular apps. Try following
angular.module('newEngagementUI.core')
.directive('customClick', customClick);
customClick.$inject = ['$rootScope'];
function customClick() {
return {
restrict: 'A',
scope: {
customClick: '&'
},
link: function(scope, element, attrs){
element.bind('click', function () {
scope.customClick();
})
}
};
}
In your template:
<div custom-click="clickFunction"></div>
And your template controller should be like:
angular.module('myApp', []).controller(['$scope', function ($scope) {
$scope.clickFunction = function () {
alert('function passed');
}
}])
Working fiddle here: https://jsfiddle.net/xSaber/sbqavcnb/1/

How to append a custom angular directive into another custom angular directive?

I have two custom angular directives and one appends the second repeatedly. The problem is that although the tag is appended, the template of the directive is not. When I manually put it in, it works.
See this jsfiddle: http://jsfiddle.net/HB7LU/5555/
Here is the code where the appending takes place:
myApp.directive('formList', function () {
return {
template: '<my-form></my-form>',
require:'^repeatableForm',
restrict: 'E',
link: function (scope, element, attrs, repeatableFormCtrl) {
scope.add = function () {
console.log("test");
element.append('appended <my-form></my-form>'); // apended<my-form></my-form> will appear but not the contents of <my-form>
};
}
};
});
You have to use $compile service to manually compile your my-form directive like this:
myApp.directive('formList', function ($compile) {
return {
template: '<my-form></my-form>',
require:'^repeatableForm',
restrict: 'E',
link: function (scope, element, attrs, repeatableFormCtrl) {
scope.add = function () {
console.log("test");
var newForm = $compile('<span>appended </span><my-form></my-form>')(scope);
element.append(newForm);
};
}
};
});
Example JSFiddle: http://jsfiddle.net/9L3whcqc/

$compile nested directive from within another directive

TL;DR; jsFiddle here.
I want to use two directives (kmOuter and kmInner) as nested directives:
<div km-outer>
<div km-inner></div>
<div km-inner></div>
<!-- ... -->
</div>
So I declared them as follows. Please note that inner directive requires outer's controller:
app.directive('kmOuter', function () {
return {
restrict: 'AC',
scope: null,
controller: function ($scope) {
this.childAdded = function () {
console.log('Child added.');
};
}
};
});
app.directive('kmInner', function () {
return {
restrict: 'AC',
require: '^kmOuter',
template: '<div>Lorem ipsum</div>',
link: function (scope, elem, attrs, kmOuterController) {
kmOuterController.childAdded();
}
};
});
That works just fine (.childAdded() is being called, among others). Now, I want to dynamically insert new instances of inner directive. This action is being triggered from some third, unrelated directive:
app.directive('kmChildAdder', function ($compile) {
return {
restrict: 'AC',
scope: {
target: '#kmChildAdder'
},
link: function (scope, elem) {
console.log(scope);
var target = document.querySelector(scope.target);
angular.element(elem[0]).bind('click', function () {
// Error is here
var newInner = $compile('<div km-inner></div>')(scope)[0];
target.appendChild(newInner);
});
}
};
});
Used like this:
<button km-child-adder="[km-outer]">Add child</button>
But it breaks with the following message:
Error: [$compile:ctreq] Controller 'kmOuter', required by directive 'kmInner',
can't be found!
.childAdded() isn't called anymore.
How can I fix this? Or maybe this design is itself broken and I should reorganise my code?
I think I made it, borrowing from #Mobin Skariya's answer.
Key was to $compile only the inserted element, not all elements:
link: function (scope, elem) {
var target = angular.element(document.querySelector(scope.target));
angular.element(elem[0]).bind('click', function () {
var newInner = angular.element('<div km-inner="param"/>');
target.append(newInner);
scope.$apply(function () {
$compile(newInner)(scope);
});
});
}
I've prepared jsFiddle with example where third, unrelated directive inserts ad compiles inner directive with working, two-way data bindings - you will find it here. Nice thing about it is that third directive (kmChildAdder) can insert inner directives taking bindings from multiple, separate controllers.
Made some edits in your code. Code given in jsFiddle link
link: function (scope, elem) {
console.log(scope);
var target = document.querySelector(scope.target);
angular.element(elem[0]).bind('click', function () {
var newInner = '<div km-inner></div>';
angular.element(target).append(newInner);
$compile(target)(scope)
});
}
Check whether this is what you expect.

How can I dynamically add a directive in AngularJS?

I have a very boiled down version of what I am doing that gets the problem across.
I have a simple directive. Whenever you click an element, it adds another one. However, it needs to be compiled first in order to render it correctly.
My research led me to $compile. But all the examples use a complicated structure that I don't really know how to apply here.
Fiddles are here: http://jsfiddle.net/paulocoelho/fBjbP/1/
And the JS is here:
var module = angular.module('testApp', [])
.directive('test', function () {
return {
restrict: 'E',
template: '<p>{{text}}</p>',
scope: {
text: '#text'
},
link:function(scope,element){
$( element ).click(function(){
// TODO: This does not do what it's supposed to :(
$(this).parent().append("<test text='n'></test>");
});
}
};
});
Solution by Josh David Miller:
http://jsfiddle.net/paulocoelho/fBjbP/2/
You have a lot of pointless jQuery in there, but the $compile service is actually super simple in this case:
.directive( 'test', function ( $compile ) {
return {
restrict: 'E',
scope: { text: '#' },
template: '<p ng-click="add()">{{text}}</p>',
controller: function ( $scope, $element ) {
$scope.add = function () {
var el = $compile( "<test text='n'></test>" )( $scope );
$element.parent().append( el );
};
}
};
});
You'll notice I refactored your directive too in order to follow some best practices. Let me know if you have questions about any of those.
In addition to perfect Riceball LEE's example of adding a new element-directive
newElement = $compile("<div my-directive='n'></div>")($scope)
$element.parent().append(newElement)
Adding a new attribute-directive to existed element could be done using this way:
Let's say you wish to add on-the-fly my-directive to the span element.
template: '<div>Hello <span>World</span></div>'
link: ($scope, $element, $attrs) ->
span = $element.find('span').clone()
span.attr('my-directive', 'my-directive')
span = $compile(span)($scope)
$element.find('span').replaceWith span
Hope that helps.
Dynamically adding directives on angularjs has two styles:
Add an angularjs directive into another directive
inserting a new element(directive)
inserting a new attribute(directive) to element
inserting a new element(directive)
it's simple. And u can use in "link" or "compile".
var newElement = $compile( "<div my-diretive='n'></div>" )( $scope );
$element.parent().append( newElement );
inserting a new attribute to element
It's hard, and make me headache within two days.
Using "$compile" will raise critical recursive error!! Maybe it should ignore the current directive when re-compiling element.
$element.$set("myDirective", "expression");
var newElement = $compile( $element )( $scope ); // critical recursive error.
var newElement = angular.copy(element); // the same error too.
$element.replaceWith( newElement );
So, I have to find a way to call the directive "link" function. It's very hard to get the useful methods which are hidden deeply inside closures.
compile: (tElement, tAttrs, transclude) ->
links = []
myDirectiveLink = $injector.get('myDirective'+'Directive')[0] #this is the way
links.push myDirectiveLink
myAnotherDirectiveLink = ($scope, $element, attrs) ->
#....
links.push myAnotherDirectiveLink
return (scope, elm, attrs, ctrl) ->
for link in links
link(scope, elm, attrs, ctrl)
Now, It's work well.
function addAttr(scope, el, attrName, attrValue) {
el.replaceWith($compile(el.clone().attr(attrName, attrValue))(scope));
}
The accepted answer by Josh David Miller works great if you are trying to dynamically add a directive that uses an inline template. However if your directive takes advantage of templateUrl his answer will not work. Here is what worked for me:
.directive('helperModal', [, "$compile", "$timeout", function ($compile, $timeout) {
return {
restrict: 'E',
replace: true,
scope: {},
templateUrl: "app/views/modal.html",
link: function (scope, element, attrs) {
scope.modalTitle = attrs.modaltitle;
scope.modalContentDirective = attrs.modalcontentdirective;
},
controller: function ($scope, $element, $attrs) {
if ($attrs.modalcontentdirective != undefined && $attrs.modalcontentdirective != '') {
var el = $compile($attrs.modalcontentdirective)($scope);
$timeout(function () {
$scope.$digest();
$element.find('.modal-body').append(el);
}, 0);
}
}
}
}]);
Josh David Miller is correct.
PCoelho, In case you're wondering what $compile does behind the scenes and how HTML output is generated from the directive, please take a look below
The $compile service compiles the fragment of HTML("< test text='n' >< / test >") that includes the directive("test" as an element) and produces a function. This function can then be executed with a scope to get the "HTML output from a directive".
var compileFunction = $compile("< test text='n' > < / test >");
var HtmlOutputFromDirective = compileFunction($scope);
More details with full code samples here:
http://www.learn-angularjs-apps-projects.com/AngularJs/dynamically-add-directives-in-angularjs
Inspired from many of the previous answers I have came up with the following "stroman" directive that will replace itself with any other directives.
app.directive('stroman', function($compile) {
return {
link: function(scope, el, attrName) {
var newElem = angular.element('<div></div>');
// Copying all of the attributes
for (let prop in attrName.$attr) {
newElem.attr(prop, attrName[prop]);
}
el.replaceWith($compile(newElem)(scope)); // Replacing
}
};
});
Important: Register the directives that you want to use with restrict: 'C'. Like this:
app.directive('my-directive', function() {
return {
restrict: 'C',
template: 'Hi there',
};
});
You can use like this:
<stroman class="my-directive other-class" randomProperty="8"></stroman>
To get this:
<div class="my-directive other-class" randomProperty="8">Hi there</div>
Protip. If you don't want to use directives based on classes then you can change '<div></div>' to something what you like. E.g. have a fixed attribute that contains the name of the desired directive instead of class.

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