Angular17 - Deferred Loading Using Defer Block

Angular 17 recently came out with several exciting updates.it has an exciting new feature called deferred loading

Lazy loading is a method that helps web apps load things like scripts only when necessary. Instead of loading everything at the start, it waits to load less important stuff until the user does something like interacting with the page or scrolling to a certain point.

Lazy loading improves the user experience by making the initial page load faster. This means users can begin using the app sooner while the less important parts load quietly in the background. It also decreases the amount of internet data needed and eases the strain on the server.

In earlier versions of Angular, we were able to load a specific part of the application later using the Router, or by using dynamic imports along with ngComponentOutlet.

Angular17 now has a @defer control block enabling lazy-loading of the content of the block. Lazy-loading also applies to the dependencies of the content of the block: all the components, directives and pipes will be lazy-loaded, too.

I will demonstrate the key aspects of lazy loading in Angular 17, such as

• Using @defer with a logical expression
• Using @defer with a declarative trigger condition

Angular 17 : New control flow syntax

Angular 17 recently came out with several exciting updates. One notable addition is the Control Flow feature. This new feature simplifies template writing by introducing a direct way to handle control flow within the template itself. Now, there's no need to rely on directives like *ngIf, *ngFor, and *ngSwitch for control flow as this new syntax streamlines the process.

This post will demonstrate a basic project using a new control flow method, moving away from the traditional directive-based approach. You can go through my other Angular post here.Let's begin right away!

Angular Project Setup

Before we start using the new feature, let's make sure you have an Angular project set up and ready to go. If you haven't done so yet, create a new Angular project using these commands with the Angular CLI:

npm install -g @angular/cli@latest
ng new ng17-control-flows

This command creates a fresh Angular project, including all the essential files and dependencies with the latest version.

Once it's set up, open the app.component.html file and remove the default Angular code. Let's add a basic HTML structure to it instead.

<h1>NG -17 :New Control Flows</h1>

Conditionally rendered control blocks: @if and @else

Let’s start with the replacement of *ngIf.

In the first example, I create a checkbox and bind it to the isChecked property.Starting with a default value of true, the checkbox appears checked, displaying the content within the @if block.The examples below are from the app.component.html template file: