Angular 16 : The Best Features and How to Use Them

 Angular 16 is the latest major release of the popular web development framework that brings many new features and improvements. In this article, we will explore some of the highlights of Angular 16 and how they can benefit your web development projects.

Angular Signals

One of the most exciting features of Angular 16 is Angular Signals, a new reactivity model that aims to enhance performance and developer experience. Angular Signals introduces new primitives such as signal, computed, and effect that allow you to define reactive values and express dependencies between them.

With Angular Signals, you can:

• Reduce the number of computations during change detection by using signals to notify the framework when the model has changed.
• Simplify the mental model for reactivity by making it clear what are the dependencies of the view and what’s the flow of data through the app.
• Enable fine-grained reactivity that will allow Angular to check for changes only in affected components in future releases.
• Make Zone.js optional in future releases by using signals instead of monkey-patching asynchronous APIs.
• Enable computed properties without the penalty of recomputation in each change detection cycle.
• Improve interoperability with RxJS by using reactive inputs.

Angular Signals is backward compatible and interoperable with the current system, so you can use it alongside existing code without breaking changes. You can also use an RxJS interop package to convert between signals and observables.

To use Angular Signals in your project, you need to install the @angular/core/signals package and import it in your component. Here is an example of how to use Angular Signals in an Angular component:

import { Component } from '@angular/core';
import { signal, computed, effect } from '@angular/core/signals';

@Component({
  selector: 'my-app',
  standalone: true,
  template: `
    {{ fullName() }}
    <button (click)="setName('John')">Click</button>
  `,
})
export class App {
  firstName = signal('Jane');
  lastName = signal('Doe');
  fullName = computed(() => `${this.firstName()} ${this.lastName()}`);

  constructor() {
    effect(() => console.log('Name changed:', this.firstName()));
  }

  setName(newName: string) {
    this.firstName.set(newName);
  }
}

In this example, we create a computed value fullName that depends on the signals firstName and lastName. We also use an effect to log the name change whenever the firstName signal changes. We can update the signals by using their set method.

Enhanced hydration

Another feature that Angular 16 introduces is enhanced hydration support. This feature allows Angular to reuse existing DOM nodes when bootstrapping on a page that was server-side rendered or compile-time pre-rendered, instead of discarding them and re-rendering from scratch.

This feature can improve page load performance in many scenarios by reducing the time to interactive and avoiding layout shifts. It can also enable better SEO and accessibility by preserving existing attributes and content.

To enable enhanced hydration in your project, you need to install the @angular/platform-browser/hydration package and import it in your main module. Here is an example of how to enable enhanced hydration in an Angular app:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { hydrateModule } from '@angular/platform-browser/hydration';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule.withServerTransition({ appId: 'serverApp' })],
  bootstrap: [AppComponent],
})
export class AppModule {}

hydrateModule(AppModule).catch((err) => console.error(err));

In this example, we use the hydrateModule function instead of the platformBrowserDynamic function to bootstrap our app. We also use the withServerTransition method to provide an app ID that matches the one used by the server-side renderer.

Faster builds with esbuild

Angular 16 also brings you Angular CLI’s new builders based on esbuild. Esbuild is a fast JavaScript bundler that can significantly improve build times in many scenarios. This preview additionally includes integration with Vite powering the CLI’s development server.

To try this new build setup, you need to update your angular.json file and replace the builder for your browser target with @angular-devkit/build-angular:browser-esbuild. Here is an example of how to update your angular.json file:

"architect": {
  "build": {
    "builder": "@angular-devkit/build-angular:browser-esbuild",
    // ...
  }
}

You can also use the --esbuild flag when running the ng build or ng serve commands.

Note that this feature is still in developer preview and may not work for all projects. You can report any issues or feedback on the GitHub repository.

Standalone component migration and scaffolding

Angular 16 also provides tools to help developers transition their apps to standalone APIs, which allow you to create components, directives, and pipes without using NgModules. Standalone APIs can simplify your app structure and reduce boilerplate code.

To migrate your existing app to standalone components, you can use the migration schematics that are part of the Angular CLI. You can run the following command to migrate your app:

ng update @angular/core --migrate-only standalone-components

This command will update your app to use standalone components wherever possible and generate a report of any issues or limitations. You can also use the standalone migration guide for more details and manual steps.

You can also create new Angular apps with standalone components by using the --standalone flag when running the ng new command. For example:

ng new --standalone

This will generate a new Angular app with standalone components and no NgModules.

Required inputs

Angular 16 also introduces a new feature that allows you to mark component and directive inputs as required. This can help you catch errors at build time if you forget to provide a required input in your template.

To mark an input as required, you can use the required option in the @Input decorator. For example:

@Component({
  selector: 'color-picker',
  template: `
    <div [style.backgroundColor]="defaultColor">Color Picker</div>
  `,
})
export class ColorPicker {
  @Input({ required: true })
  defaultColor: string;
}

In this example, the defaultColor input is marked as required. If you use this component in your template without specifying the defaultColor input, Angular will report an error at build time.

Other improvements

Angular 16 also includes many other improvements and bug fixes across the framework, compiler, CLI, and components. Some of them are:

• Support for TypeScript 4.9 or later
• Support for Node.js v16 or v18
• Improved error messages for unknown elements and properties
• Improved type inference for template variables
• Improved support for Web Workers
• Improved support for Tailwind CSS
• Improved support for differential loading
• Improved support for lazy loading modules
• Improved support for custom elements
• Improved support for i18n

For a more comprehensive list of changes, see the changelogs on GitHub.

Conclusion

Angular 16 is a major release that brings many new features and improvements to the web development framework. You can update your Angular apps to Angular 16 by using the Angular Update Guide. You can also try out some of the developer preview features like Angular Signals, enhanced hydration, and esbuild builders.

Links 

 Angular 16. Angular 16 is the latest major release… | by Faizan Shaikh | May, 2023 | Medium