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Let’s say I wrote a component that I want to be reusable. The Angular 2 framework system has other interesting possibilities, for example, Template reference variables. It does this by taking the Angular component and compiling it into a web component. Configurable templates In Angular… The list component looks like this: To render this it only takes in a listRef and the data to render the list. Open for comments and suggestions. This quickly becomes tiresome because it is not scaling to more complex usages. An example of this is a simple questionnaire that should be dynamically rendered using json data from an API. Here, we send header via an attribute selector and footer via a class selector. To illustrate how you should keep components reusable and maintainable we are going to create a reusable card list component, which can toggle between cards and a list. When generating a new app, the CLI prompts you to select CSS or a CSS preprocessor. There is a subtle difference between using templateRef vs. using ng-content because of how Angular’s lifecycle management works. This normally involves iterating over the provided data and follow a convention for … To use the Angular router, an app needs to have at least two components so that it can navigate from one to the other. The component gets properly created, a service instance is created and injected. /example1/foo and /example2/foo not only is the ContainerComponent being reused (as expected), … This will provide HttpClient to the component's class, making it available to the component via this.httpClient.. As you probably know, Angular is all about building UI components. abstract changeDetectorRef: ChangeDetectorRef: Read-Only. Let’s see how you can reuse the component and have the ability to provide custom templates for different elements of the view. This component instance. Some styling is applied to these cards to make them wrap nicely: Now we can display the card-list component and easily change the cards or list by simply changing the template ref provided. abstract hostView: ViewRef: Read-Only. We’ll see later how the parent component takes advantage of this property. However, the template is not inherited into ChildComponent as it is part of the @Decorator. Angular Elements is a new package in Angular that helps us publish Angular components as custom elements. Filed Under: Angular Tagged With: Angular, ng-content, reuse, templateRef, Pingback: The Hardcoded, Dynamic and Hybrid Approach in Angular Apps – Christian Lüdemann IT(), How to Accelerate Your Angular Career and Double Your Income, Click to share on Twitter (Opens in new window), Click to share on Reddit (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Tumblr (Opens in new window), Click to share on Google+ (Opens in new window), Click to share on LinkedIn (Opens in new window), Click to share on Pocket (Opens in new window), The Hardcoded, Dynamic and Hybrid Approach in Angular Apps – Christian Lüdemann IT. The first way only works for simple components as they will become harder to use and maintain if the complexity grows because of lots of input to be configured for the specific use case and as well as a lot of “duct tape” programming to handle all the different applications of the reusable component. TL;DR. Point templateUrl of your ChildComponent to the Base component’s template file. Currently, we will reuse the same component instance when its params change. Check out Angular Architect Accelerator. Previously, due to the way the AngularJS and Angular clean-up processes interfere with each other when removing an AngularJS element that contains a downgraded Angular component, the data associated with the host element of the downgraded component was not removed. For instance, if we talk about Angular 7, it only allows you to use Angular components inside other frameworks. Been there done that, wasn’t fun. Child points to the template of the Base. ElementRef is a service that grants direct access to the DOM element through its nativeElement property. There are two main ways to create reusable components in Angular: The choice of which technique to reuse components you should use is determined by the desired flexibility. The content is likely still applicable for all Angular 2 + versions. The same applies to software development, but it takes some know-how to efficiently create reusable components that will be flexible enough for your use cases while being worth the effort of making it reusable. Also, it may not be clear at the beginning, but it paves the path for further design compromises in future, OR you are not able to leverage the powers of object-oriented programming. To reuse where it is possible is a natural instinct in all aspects of life. We were planning to implement support for custom "reuse" strategies. We can configure the DI framework in Angular in three main ways. We want to create a card-list component that takes in a listRef, cardRef and data to be shown and is used like this: Note how simple the interface of the cards-list component is because we simply utilize templateRefs and map data using let-todos="data" which will map data to todos when we are passing data to a templateRef with ngTemplateOutletContext. (Would be awesome if someone can tell me how to make it relative to the Angular app root, or node_modules. This is an alternative to #39921. Before we continue with the main topic of this article — “how to write reusable Angular components”, let’s take a quick look at a great tool that actually lets you share and collaborate on individual reusable components. Such libraries provide common reusable components such as tabs, date pickers, collapsible menus, and much more. content_copy ng new routing-app --routing. The single responsibility principle is the idea that pieces of your app should have one purpose. We can configure a provider on the NgModule, on a component’s or directive’s providers property, and on a component’s viewProviders property. Similarly, for the CSS file. You create a BaseComponent class, and do ChildComponent extends BaseComponent. This is useful when you need to have a different look and feel for your child component. https://live.staticflickr.com/5481/14581168505_1161f27596_b.jpg. It will also help to reduce the depth of Container components to reuse the layout across different routes. To put all this into practice we created a card list reusable component for rendering an array of data as either a card or a list. Open the terminal, go to shared folder and type: Go to cards-list and create the cards and list components: Since the only input we are working with here is template refs and data, to be shown in the template refs, we are going to have very simple presentation components. You cannot solve this problem. This gets very painful as the amount of input keeps growing, as well as the complexity of the reusable component as it should handle more edge cases, in the end making the component harder to reuse than if it were simply copied and modified to serve the purpose. Class inheritance 2. The above example could be tweaked further to make the base class generic, i.e. 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. What you want to do instead is allow for an external template to plug into the component using either templateref or ng-content (check my plugin architecture post for an example of this with ng-content). A template is a form of HTML that tells Angular how to render the component. Angular 10/9/8 provide to create your custom component. Angular’s development team strongly encourages following the single responsibility principle when creating components and classes. There are several excellent component libraries out there that you can use to build your own application, such as Angular Material, Clarity or Kendo UI to name a few. The card and list row components are created like presentation/dumb components in the shared folder: The card component is created with Angular Material directives: The list row is created with Bootstrap (got to spice stuff up): These are being used as template references in the reusable component. Templates and viewslink. In this post, I will show you how to use this package in your Angular application. In this article I will present how to reuse a common logic in an Angular application. However, when switching between various foo routes, e.g. Each component gets encapsulated with all its dependencies and setup and pushed into a private/public collection on Bit’s cloud where it can easily be discovered by others. You define a component's view with its companion template. The parent component cannot data bind to the child's start and stop methods nor to its seconds property. - promote code reuse. I’m Christian, a freelance software developer helping people with Angular development. 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