You have probably heard it as many times as I have. "Do all your DOM manipulation in directives". But no one ever seems to say what could happen if you actually do DOM manipulation outside a directive in Angular.
I have a problem that I managed to reproduce in this Plunk
I have made a very simple directive that just outputs the element to the console.
app.directive('dirre', function(){
return {
link: function(scope, element, attrs){
console.log({message:"dirrens linkFn", element: element, count: element.length})
}
}
});
I have two identical jquery UI accordions, the only difference is the way they are called. One is called in a controller and the other one in a directive. Calling accordion from a controller is of course something bad.
As you can see if you run the application there is a situation where one of the dirre-directives does not seem to have an element but there are no errors.
The same thing happens in a big application I'm working with right now. The problem seems to be that someone in our team decided to call Jquery UI's accordion in a controller and not in a directive.
I haven't been able to step through the code to see what actually happens but I strongly suspect that the DOM is modified while Angular is compiling and something goes wrong.
Is this a plausible explanation?
Is this an example of what can go wrong if you do DOM manipulations outside a directive?
The controller and the directive links function are called asynchronously.
Usually you can see directives being built before the main Controller complete. When the controller terminates, the directives update their watched variable (ngModel, $watch(something)...). Basically this is done with promises.
The link/compile function however is not called again. You have to compile, watch, apply the new DOM. Which basically means writing the similar code to angularjs.
Related
I have a one-page site that I am building out and this is my first time using Angular on a site. Building it on top of Laravel too for the backend but that is beyond the scope of this question.
I need to be able to open a modal on a main page view which will add a new resource (e.g. a new client) or edit a resource. I want to somehow get the form's html inside the modal body when the $uibModal.open()'s controller is called and set the $scope.modalBody equal to the injected items.modalBody (the only way this works is if I use:
$scope.modalBody = $sce.trustAsHtml(items.modalBody);
The only problem now is that anything inside the HTML body, Angular will not use it's magic and do any data-binding. It is still in the raw form of
{{ object.property }} or since I'm using Laravel and avoiding conflict with the Blade template engine:
<% object.property %>
See screenshot:
screenshot
I have been banging my head against the wall on this one...I have tried putting $scope.$apply() in my directive and my controller, neither of which worked. I have a feeling that is the source of my problem though. I have also tried making the html just a <new-client></new-client> directive and using templateUrl: 'views/clients/add.php' which would be ideal, but the template is not being included inside the <new-client></new-client>.
I'm using ui-bootstrap 0.14.3 and Angular 1.4.8.
Could this be a bug? Or am I doing something wrong? Anyone have a better way of getting a form into my modal? Let me know what code you want to see so I don't clutter this post with unnecessary code blocks.
I have come across a similar issue with using jQuery's AJAX to receive template strings and append it to a server.
So when HTML is added via jQuery, bound html string, etc., angular doesn't know it needs to automagically compile this data.
What you need to do is use the $compile service, to $compile your html and then attach the correct $scope to it:
`$compile('jQuerySelectorReturningHtmlOrAnHTMLStringThatNeedsToBeCompiled')($scope);`
There are multiple examples in Angulars Documentation for $compile that can give you an idea of what is happening. I think by what you have described the same thing is happening here in your situation.
The key is to call this $compile service function after the html has been bound to the page.
EDIT:
There are a few other options based on some comments, that will serve as a viable solution to rendering this content on your view. For example a directive that takes a string attribute representing the HTML string of your desired view.
1. Modify your directive template in the compile step:
You have the ability to modify your template before the directive compiles and binds any attributes to it, to that directives scope:
app.directive('myAwesomeCompileStepDirective', [myAwesomeCompileStepDirectivef]);
function myAwesomeCompileStepDirectiveFn() {
return {
restrict: 'EA',
compile: function compileFn(tAttrs, tElement) {
//Here you can access the attrs that are passed into your directive (aka html string)
tElement.html(tAttrs['stringThatYouWantToReplaceElementWith']);
return function linkFn(scope, element, attrs, controller, transcludeFn) {
//if all you want to do is update the template you really don't have to do anything
//here but I leave it defined anyways.
}
}
}
}
You can view a file I wrote for a npm component which uses this method to modify my directive template before it is compiled on the page & you can also view the codepen for the complete component to see it in action.
2. Use $compile service to call $compile in link function using directive attrs.
In the same way as the aforementioned method, you can instead inject the $compile service, and call the function mentioned above. This provides a bit more work, for you but more flexibility to listen to events and perform scope based functions which is not available in the compile function in option 1.
I have some code that creates and registers some animations inside a controller. Unfortunately, whenever I register an animation inside a controller, it does not seem to initialise (The function never gets called.)
I have created a plunker to illustrate the issue. In this, I call"createAnim1" outside the controller and the animation functions correctly. I call "createAnim2" inside a controller, and the animation does not function.
createAnim1();
app.controller('main', function($scope) {
createAnim2(); //This animation does not work
});
The createAnim function are in the form:
app.animation('.anim1', function() {
return {
...
}
});
Am I missing something obvious? The $animate and $animateProvider documentation don't seem to contain anything relevant to this.
I assume this has to do with the fact that a compilation has already happened, and some step required to initialise the animations is being missed? Is there some way to get around this?
PS: I have only been using angular since last week, so I'm not well versed on the internals.
Edit:
After the comments from Alex, I think it is worth clarifying what I am trying to do:
I have some code which generates css class animation selectors and appends them to the document head. If the browser does not support transitions, the code generates a jquery animation equivalent. I have tried to create a factory to expose this code via DI, and it is when this code is run (From inside a controller) the animation is never able to trigger (The initialisation code is never run).
I have multiple custom directives in my ngApp. The demo code is:
<top-nav></top-nav>
<left-sidebar></left-sidebar>
<div class="content">
....
</div>
The height of the 'left-sidebar' needs to be adjusted according to the height of the 'top-nav'.
Similarly there are other interdependent UI tasks. I want to run the post-load code (say app.initializeUI();) only after ALL the directives have been loaded and rendered.
Now, How do I achieve that?
EDIT :
Currently I am using the following code :
App.run(function($timeout){
$timeout(function(){ app.init() },0);
});
This runs fine, however, I am not sure this is the perfect way of doing this.
EDIT 2:
For people who want to avoid setting styles in js - use CSS Flexbox. I find it much better than calculating heights post page load. I got a good understanding of flexbox here
I would create an attribute directive with isolated scope, set terminal=true and add it to your body tag. Then in your link function, setup a $watch - isInitialized which is initially false. In your $watch handler, call your app.init(), and then de-register the $watch, so that it is always initialized once.
Setting up a terminal directive has consequences - no other directive can run after the terminal directive on the same element. Make sure this is what you want. An alternative is to give your directive the lowest possible value so that it is compiled first, and linked last.
The important pieces to this solution are:
By adding your Directive to the body tag, you ensure that it is linked last.
By adding a $watch, you ensure that all other directives have gone through a digest cycle, so by the time your $watch handler is called, all other directives should have already rendered.
Note of caution: The digest cycle may run several times before scope changes stabalise. The above solution only runs after the first cycle, which may not be what you want if you really want the final rendering.
In my angular app, directives are working fine during the first visit, but once a page been visited twice, all the directive link function gets called twice too. Say I am on page A, click a link to go to page B and then back to page A, all directives on page A will execute the their link function twice. if I refresh the browser it will become normal again.
Here is an example where the console.log will output twice when the second visit.
#app.directive 'testChart', ["SalesOrder", (SalesOrder) ->
return {
scope: {options: '='}
link: (scope, elem, attrs) ->
console.log("............checking")
SalesOrder.chart_data (data) ->
Morris.Line
element: "dash-sales"
data: data
xkey: 'purchased_at'
ykeys: ['total']
labels: ['Series a']
}
]
Any idea?
Update
My Route
when("/dash", {
templateUrl: "<%= asset_path('app/views/pages/dash.html') %>",
controller: DashCtrl
}).
so my chart is duplicated
also make sure you are not including your directive in your index.html TWICE!
I had this exact same problem.
After a loooooong time digging around I found that I hadn't used the correct closing tag which resulted in the chart being called twice.
I had
<line-chart><line-chart>
instead of
<line-chart></line-chart>
The link() function is called every time the element is to be bound to data in the $scope object.
Please check if you are fetching data multiple times , via GET call. You can monitor the resource fetching via Network tab , of chrome debugger.
A directive configures an HTML element and then updates that HTML subsequently whenever the $scope object changes.
A better name for the link() function would have been something like bind() or render(), which signals that this function is called whenever the directive needs to bind data to it, or to re-render it.
Maybe this will help somebody...
I had a problem with directive transclude, I used a transclude function which was adding child elements and also at the same time I forgot ng-transclude in directive template. Child elements were also directives and their link function was called twice!
Spent some time on this one..
More in details:
I had a "main" directive and "child" directives, idea was to use one inside another, something like that:
main
child
child
So problem was that link of "child" directive was called twice, and I didn't understand why,
Turned out I had ng-transclude in "main" directive template (I am posting it as it is in PUG format, sorry for that):
md-card(layout-fill)
md-card-content(flex)
.map-base(id="{{::config.id}}", layout-fill)
ng-transclude
and also in link function of "main" directive I called transclude function:
link: function($scope, $element, $attrs, controller, transcludeFn) {
$element.append(transcludeFn());
}
I think I just tried different combinations and forgot about that, visually everything was ok, but link was called twice and code was running twice and logic was broken..
So problem is that you can't have both and you have to choose one of the ways.
Hopefully now it is more clearer.
In my case I had a main-nav and sub-nav that both called a directive by its name attribute. Since the first instance already set the scope needed the second sub-nav the 2nd call wasn't needed. Incase anyone has a similar issue.
Update: Fiddle w/ full solution: http://jsfiddle.net/langdonx/VXBHG/
In efforts to compare and contrast KnockoutJS and AngularJS, I ran through the KnockoutJS interactive tutorial, and after each section, I'd rewrite it in AngularJS using what little I already knew + the AngularJS reference.
When I got to step 3 of the Creating custom bindings tutorial, I figured it would be a good time to get spun up on Angular Directives and write a custom tag. Then I failed miserably.
I'm up against two issues that I haven't been able to figure out. I created a new Fiddle to try and wrap my head around what was going on...
1 (fiddle): I figured out my scoping issue, but, is it possible to just passthrough ng-click? The only way I could get it to work is to rename it to jqb-click which is a little annoying.
2 (fiddle): As soon as I applied .button() to my element, things went weird. My guess is because both Angular and jQuery UI are manipulating the HTML. I wouldn't expect this, but Angular seems to be providing its own span for my button (see line 21 of the JavaScript), and of course so is jQuery UI, which I would expect. I hacked up the HTML to get it looking right, but even before that, none of the functionality works. I still have the scope issue, and there's no template binding. What am I missing?
I understand that there's an AngularUI project I should be taking a look at and I can probably pull off what I'm trying to do with just CSS, but at this point it's more about learning how to use Directives rather than thinking this is a good idea.
You can create an isolated scope in a directive by setting the scope parameter, or let it use the parent scope by not setting it.
Since you want the ng-click from parent scope it is likely easiest for this instance to use the parent scope within directive:
One trick is to use $timeout within a directive before maniplulatig the DOM within a templated directive to give the DOM time to repaint before the manipulation, otherwise it seems that the elements don't exist in time.
I used an attribute to pass the text in, rather than worrying about transclusion compiling. In this manner the expression will already have been compiled when the template is added and the link callback provides easy access to the attributes.
<jqbutton ng-click="test(3)" text="{{title}} 3"></jqbutton>
angular.module('Components', [])
.directive('jqbutton', function ($timeout) {
return {
restrict: 'E', // says that this directive is only for html elements
replace: true,
template: '<button></button>',
link: function (scope, element, attrs) {
// turn the button into a jQuery button
$timeout(function () {
/* set text from attribute of custom tag*/
element.text(attrs.text).button();
}, 10);/* very slight delay, even using "0" works*/
}
};
});
Demo: http://jsfiddle.net/gWjXc/8/
Directives are very powerful, but also have a bit of a learning curve. Also in comparison of angular to knockout, angular is more of a meta framework that in the long run has far more flexibilty than knockout
Very helpful reading for understanding scope in directives:
https://github.com/angular/angular.js/wiki/The-Nuances-of-Scope-Prototypal-Inheritance