Angular destroy component instance

NativeScript Angular keeps navigated components alive on a stack. This is great for performance since the framework doesn't have to work as…. This is great for performance since the framework doesn't have to work as hard to recreate the components that you might return to. However, sometimes you might need manual control over the component life cycle, and you may need to call ngOnDestroy on a component when the Page unloads.

This short tutorial will show you how to do that. In a NativeScript Angular application, when you navigate between top-level components, they are placed on a stack and kept in memory. This is great for performance as the components won't have to be recreated as you navigate back and forth between them.

However, there are some occasions where this isn't ideal and it would be preferable for a component to be destroyed when it's navigated away from. For instance, the component could be a memory hog and so it would be a good idea to not have it using up resources when not in use. To make a component destroy itself when the user navigates away from it, you have to make the component call its ngOnDestroy lifecycle hook when the page unloads. This is done by leveraging the host page's life cycle.

In NativeScript Angular applications, you have components which live inside pages. Each page has its own lifecycle hooks and each component also has its own lifecycle hooks. So to force a component to destroy itself, it's going to have to interact with its host page's lifecycle hooks. Let's see how this can be done. For the demo app, we have a NativeScript Angular app that displays a list view—with the names of football players—and on tapping on one of the list view items, you will navigate to the footballer's detail page.

As mentioned previously, in NativeScript Angular, Pages host components, so for our app, we have a page that hosts the list of items, i. When we navigate from the list view to the details view, we are not only triggering the lifecycle events for our components, we're also triggering the lifecycle events for our NativeScript pages. Let's demonstrate this with a common scenario where we need to clean up after ourselves after navigating away from a component the ItemsComponentin our case.

Now, let's add the ngOnDestroy lifecycle hook handler to the component and see if it will be called when the page unloads. On running the app and navigating away from the list view, we don't get the logged out message, so ngOnDestroy wasn't called.

This is because the component wasn't destroyed, but it was put on a stack. When we navigate back and forth from component to component, the components don't get destroyed, they are just added to and popped off the stack. To force a component to be destroyed, you use the HostListener from the Angular Core library.

When using HostListeneryou specify the event you want to listen to on the host of the component. In our case, we listen for the unloaded event so that when the page is unloaded, ngOnDestroy will be triggered. We can then release resources and cleanup in this function. On running the app, we now get the logged out message which means that we've succeeded in forcing that component to destroy itself. That's it, folks!Today I will show you guys how to create dynamic component using service in Angular and how to safely destroy component when we dont need it anymore.

And finally we will learn how to interact with Input and Output property when using dynamic component. We put the directive dynamic-ref to ng-content so that we can let Angular know where the component will be render.

So what I did here is create private variable to hold a ComponentRef instance. The ComponentRef instance allow you to destroy the dyanamic component. The createComponent simply take 2 params. Then the destroyComponent method simply check the componentRef instance exist or not if it exist we will destroy the component. Notice 2 line below dynamiCreateComponent is how I can communicate with the dynamic component using their Input and Output property. So I can listen on the click event happend in the dynamic component and invoke an action in my parent component.

So last thing when my parent component destroy it will call destroyComponent method to destroy dynamic component to prevent memory leak. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email.

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Email required Address never made public. Name required.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I designed a dynamic form.

Here is what you need to know about dynamic components in Angular

It works well in Angular 5 version. However, after upgrading the Angular version to 10, it started malfunctioning. It doesn't give this error when I close AOT. This time, ngModel is not working. How can I solve this problem without closing AOT? Learn more. Asked 5 days ago.

Create and destroy dynamic component in Angular

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Force Component Destroy by Using Page Life Cycle in NativeScript Angular

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I have an Angular app and it have a button to switch between two components. I found an issue when i'm playing with the button a bit and sometimes a component is inheriting some behavior from the other component, so I'm looking for a way to start a fresh and clean instance each time i'm switching. I tried to do some unsubscribe in the ngOnDestroy but it won't help much! Disclaimer : I do not prefer writing code that handles creating and destroying components manually.

You should of course deal with your code during creation and destruction using ngOnInit and ngOnDestroy. However, I assume you are using ComponentFactoryResolver. This ensures that no information from previous component is held within the viewContainerRef while loading new instances.

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Learn more. What is the best way to destroy a component instance in angular? Ask Question. Asked 2 years ago. Active 2 years ago. Viewed 3k times. Roi Sadika Roi Sadika 2 2 silver badges 12 12 bronze badges.

angular destroy component instance

How do you switch using button. Active Oldest Votes. If that is the case, you can use : viewContainerRef. Saurabh Tiwari Saurabh Tiwari 2, 3 3 gold badges 26 26 silver badges 56 56 bronze badges.

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Sign in to your account. It would be nice if we could tell angular not to destroy components when we navigate out of them, even if the next component is of a different type.

This could be useful, for example, when building a window management system, where users can navigate through different windows components without the need for recovering the whole state.

The existing canReuse hook is not useful for this use case, since it only allows us to reuse components if the previous and the next component have the same type.

Hi Misko, thanks for you answer! I've actually done that and it works fine. Take this just as a suggestion. There may be a lot of state that must be stored for complex windows and doing that is error prone and painful. It would be nice if angular 2 had this possibility. I agree with cangostaI think this could be a very useful feature in certain scenarios.

Can someone please weigh in on this? I'd be interested in seeing this be discussed in a somewhat technical fashion. Picture the scenario when you need to navigate through various routes. If you save state in a higher level component, you most likely will save the model. What about the state of the view? Imagine you have in one view a tab component, with the 3rd tab selected.

When getting back, you want the 3rd tab to be selected.In this article, we will learn how to create components in Angular dynamically. First, we need a component. For the simplicity, we are going to use a simple alert component that will take as Input the alert type. In Angular, this place is called a container. In the my-app component, we are creating a template element.

We are also using the hash symbol to declare a reference variable named alertContainer. The template element is the placeor in the Angular world, the container. Note: The container can be any DOM element or component. Now we need to get a reference to our template element in the my-app component.

We can get a reference to the template element with the ViewChild decorator that also takes a local variable as a parameter. The default return from the ViewChild decorator is the component instance or the DOM element, but in our case, we need to get the element as ViewContainerRef.

As the name suggests, ViewContainerRef is a reference to a container. ViewContainerRef stores a reference to the template element our container and also exposes an API to create components. Before we proceed to the createComponent method, we need to add one more service.

The resolveComponentFactory method takes a component and returns a ComponentFactory. You can think of ComponentFactory as an object that knows how to create a component. As you can see the ComponentFactory exposes the create method that will be used by the container ViewContainerRef internally. Now for the final step. Every time we need to create the component we need to remove the previous view, otherwise, it will append more components to the container.

The resolveComponentFactory method takes a component and returns the recipe for how to create a component. We are calling the createComponent method with the recipe. Internally this method will call the create method from the factory and will append the component as a sibling to our container.

Now we have a reference to our new component, and we can set the type Input. You can also subscribe to a component Output like this:. The last step is to add your dynamic components to the entryComponents section:. Sign in. Dynamically Creating Components with Angular. Netanel Basal Follow. Netanel Basal Articles for badass Angular Developers. Articles for badass Angular Developers. Written by Netanel Basal Follow. More From Medium. Netanel Basal in Netanel Basal. Exploring the Various Decorators in Angular.Sign In Join.

Angular destroy component event. We just learned that a change means new reference. May 01 An Angular application is a tree of components. As in an abstraction the Angular team can change the code under the hood without you even noticing because they are not breaking the contract they published.

angular destroy component instance

This could be useful for example when building a window management system where users can navigate through different windows components without Welcome to the AngularJS API docs page.

Angular provides the createCustomElement function for converting an Angular component together with its dependencies to a custom element. That gives you a reference to the child component and the ability to access any of its properties or methods from within the parent template. In this post we take a look at getting started with the Google Maps component. Built with Angular 7. Our component will have one input the original html and one output the modified html.

Expected behavior. We can check to see if the current animation is the snackbarOut animation. Use stopPropagation to avoid double event handler The Component is a decorator which uses configuration object to create the component and its view.

Jan 03 You can easily use show hide toggle div on click event in angular 6 angular 7 angular 8 angular 9 and angular 10 application. The template element is the place or in the Angular world the container. In this lesson I provide four different methods for sharing data between Angular components. We can update the media item component and make use of the output decorator to provide Aug 12 Angular Material Tabs create a beautiful layout filled with animation.

Angular 8 9 provides every kind of event types to deal with the specific situation.

angular destroy component instance

A custom component that takes the type of a component as input and creates an instance of that component type inside itself. Happy coding The event will be fired once the component rendering is completed. Like any natural lifecycle each component has its lifecycle events like birth life events and death.

Jul 24 Angular apps are built as a hierarchy of components. Container component templates are hardly worth testing since they only contain data bindings. Minimal reproduction of the problem with instructions What is the motivation use case for changing the behavior Environment Understanding Components.

You can destroy a component using destroy method on the componentRef. There are 8 different stages in the component lifecycle. Apr 14 Angular 10 adheres to the modular and component based architectures. In the last passing data to child component tutorial we built a counter in the parent component.

Now when you execute it in the browser the service property will be changed since the value of it is changed in app. Mar 28 What is Angular Component Angular Component is an Angular directive that has its own view or templates independently.


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