Dynamic Component Injection Made Easy with Angular CDK Portals
As Angular developers, we’re no strangers to building complex apps by combining multiple components. However, when it comes to injecting dynamic components or UI templates into another component, things can get tricky. That’s where Angular CDK Portals come in – a powerful feature that simplifies dynamic content injection while promoting clean code and flexibility.
The Problem with Traditional Approaches
Before we dive into Portals, let’s explore the limitations of traditional methods like ngComponentOutlet and ComponentFactoryResolver. These approaches require the host component to reference the injected component directly, leading to tight coupling and making testing and maintenance a nightmare.
Introducing Angular CDK Portals
Portals provide a flexible and clean alternative to injecting content into an Angular component. A Portal consists of two key parts: the UI element (component, templateRef, or DOM element) to be rendered, and the slot where the content will be rendered – known as the PortalOutlet.
Setting Up Portals
To get started with Angular CDK Portals, you’ll need to install the necessary package and import the CDK module in your app.module.ts file. From there, you can create portals using ComponentPortal, TemplatePortal, or DomPortal.
Creating a Portal
In our example, we’ll use the cdkPortal directive to create a portal from a template. We’ll wrap ng-content inside an ng-template and add the portal directive. This allows us to project contents from other components into the portal.
Defining the PortalOutlet
Next, we’ll create a placeholder with an ID in our ActionComponent and use document.querySelector to get hold of the DOM element. We’ll then create a DomPortalOutlet and attach the portal to it, injecting the portal into the placeholder.
Putting it all Together
With both the portal and PortalOutlet defined, we can attach the portal to the PortalOutlet, injecting dynamic content into the ActionButtonComponent. This approach allows us to decouple our subcomponents from the external data entities, making them reusable and easier to maintain.
Passing Context Instead of Contents
In some cases, you may need to pass contextual data into the portal. You can do this using the context property for TemplatePortal or token injection for ComponentPortal.
Final Results
By leveraging Angular CDK Portals, we’ve successfully injected dynamic content into our dashboard components while maintaining a clean and flexible architecture. Our subcomponents are now loosely coupled, focusing solely on rendering content correctly.
Summary
In this article, we’ve explored the power of Angular CDK Portals in injecting dynamic content into components. With its flexibility and clean separations, Portals provide a robust solution for building complex apps. Try applying this technique in your own projects and experience the benefits of Angular CDK Portals firsthand!