When you want to defer, skip, repeat, or otherwise control the linking and rendering of some part of the UI. Here’s what such a directive might look like, without using any transclusion yet:. Angular scopes get destroyed when their parents do, but if the parent of our transclusion scope is the outer scope, there are no guarantees about how long it’ll stay around. Stop there, AngularJS is not wrong but probably you. It’s a nice start for such a component, but there’s one unfortunate downside to it: The built-in ngRepeat directive also uses element transclusion, though studying its source code is not quite as easy as with ngIf because of the various ways you can use ngRepeat and all the optimizations it contains. While the book covers the internals of the API, this article is an attempt to write the user guide I wish I’d had before.
One of the “input parameters” of myCard is the body content. Input restricted for Element, so every input has one. Sign up using Email and Password. This code is written without jQuery. The transclusion just occurs one level higher than normally. However, there are only some attributes that are built for method binding, such as ng-click, ng-blur, ng-on-change, etc, that expect methods as paremeter. As discussed earlier, Angular will manage the creation of transclusion scopes for you, so most of the time you don’t have to do anything and things will just work.
Another use case for element transclusion is if you want to link and attach part of the DOM several times. The transclusion function optionally takes a scope object as the first argument before the clone attach function. That’s a bit clumsy transvlude not idiomatic Angular code. Sign up using Email and Password. In Input directive I broadcast every change to element’s scope:. For example, you could angularjss a directive like townView here, that has full control over what data it shows, but allows passing in a dynamic template for how the data is shown:.
Do note that using transclusion like this alters the behavior anfularjs templates in a way that the directive user may not expect: For one thing, it gives you an escape hatch if you run into a corner case with scope management that it doesn’t handle. However, there are only some attributes that are built for method binding, such as ng-click, ng-blur, ng-on-change, etc, that expect methods anglarjs paremeter. So the best practice of this approach is creating a directive that includes all manipulations and use the directive throughout your app.
You can, however, choose not to let Angular create the transclusion scope and provide your own instead. If you look at the source code of ngIfyou should now be able to understand what it’s doing: Based on what I’ve heard, I’m not alone in this. If the element itself becomes part of the transclusion, what exactly is left in angulagjs DOM as the container of the transcluded content? Here, transclusion creates a child scope and you can get the name variable, right, but whatever change you make to this variable will stay there.
But, if we dig a bit deeper into it, the difference is actually more fundamental. There’s nothing magical about it, which is evident if you look at its source code.
Say goodbye to fixing problems by trial and error and hello to reasoning your way through them. Even the word “transclusion” seems to be uncomfortable to many people, and is often criticised for being a made-up one.
A Guide To Transclusion in AngularJS
We’ve seen how the transclusion function works: Sign up or log in Sign up using Google. Say goodbye to fixing problems by trial and error and hello to reasoning your way through them eBook Available Now.
AngularJS – Watch for model of transcluded element – Stack Overflow
Let’s now turn our attention to an alternative way you can use transclusion: Controllers are the places where you define your dependencies, bind your data to the view and make further business logic.
This is essentially a hugely simplified watcn of ngRepeat. Transclusion is nice for static bits of HTML, but what if you use it with dynamic content? In AngularJS, I have directive with basic transclusion. Instead angularks using myContentTransclusionPointyou can just use ngTransclude:.
There is one more reason you might want to use the clone attach function: The difference between this kind of transclusion and the regular kind is in what becomes the transcluded content: There’s a problem with this implementation, which is that it is leaking watcg. The four first ones being the element, the scope, the attributes, and the required controllers.
One of the “input parameters” of myCard is the body content. So we can introduce a directive like myContentTransclusionPointwhich uses the transclusion function that it gets from the parent.
7 deadly sins of AngularJS – Eteration A.Ş.
In our case, that’s the myCard isolate scope:. Go ahead and try it! We’re forced to cram the body content of the card into one big string in the my-content attribute. Though I’ve used it from time to time, using it always felt uncomfortable.
The elements given to the clone attach function will not be the exact same ones originally sucked into the transclusion.