Whats New In Angular 18

What’s New in Angular 18?

Angular 18 brings significant innovations in state management, data handling, and application logic flow. This latest version reduces state complexity, enhances performance, and provides better tools for developers to manage and maintain their applications. Here are the key features introduced in Angular 18:

1. Zoneless Applications

Traditionally, Angular has relied on zone.js for change detection, which has posed various issues in performance and developer experience. Angular 18 introduces experimental APIs for zoneless change detection, enabling developers to remove zone.js from their projects and enhance performance.

Example:

import { bootstrapApplication } from "@angular/platform-browser";
import { provideExperimentalZonelessChangeDetection } from "@angular/core";

bootstrapApplication(AppComponent, {
  providers: [provideExperimentalZonelessChangeDetection()],
});

In components, signals are used for managing state changes without zone.js:

import { Component, signal } from "@angular/core";

@Component({
  selector: "app-root",
  template: `
    <h1>Hello from {{ name() }}!</h1>
    <button (click)="handleClick()">Go Zoneless</button>
  `,
})
export class AppComponent {
  protected name = signal("Angular");

  handleClick() {
    this.name.set("Zoneless Angular");
  }
}

2. Route Redirects with Functions

Angular 18 allows the use of functions to handle route redirects, providing greater flexibility in routing. This feature enables dynamic redirection based on URL parameters or other conditions.

Example:

import { Routes, RouterModule } from "@angular/router";
import { ErrorHandler, inject } from "@angular/core";

const routes: Routes = [
  { path: "first-component", component: FirstComponent },
  {
    path: "old-user-page",
    redirectTo: ({ queryParams }) => {
      const errorHandler = inject(ErrorHandler);
      const userIdParam = queryParams["userId"];
      if (userIdParam !== undefined) {
        return `/user/${userIdParam}`;
      } else {
        errorHandler.handleError(
          new Error("Attempted navigation to user page without user ID.")
        );
        return `/not-found`;
      }
    },
  },
  { path: "user/:userId", component: UserComponent },
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule],
})
export class AppRoutingModule {}

3. TypeScript 4.7 Support

Angular 18 supports TypeScript 4.7, introducing new features like template literal types, improved readonly support, and import types. These enhancements improve code modularity and typing accuracy.

4. Latest ng-template API

The new ng-template API simplifies template creation and reuse, reducing the need for specific selectors and making templates more versatile.

5. Upgraded Debugging Tools

New debugging tools in Angular 18 provide better insights into application state, source maps, component trees, data bindings, and performance profiling, making it easier to debug and test applications.

6. New Official Documentation Website

The new official documentation website, angular.dev, offers a contemporary experience with hands-on tutorials, a live playground, enhanced search, redesigned guides, and streamlined navigation.

7. Hydration Support in CDK and Material

All Angular Material and CDK components now support hydration, ensuring consistent rendering behavior across different environments.

8. Unified Control State Change Events

Forms in Angular 18 introduce a new events property in FormControl, FormGroup, and FormArray classes. This property enables granular tracking of changes in value, touch state, pristine status, and control status.

Example:

import { FormControl, Validators } from "@angular/forms";

const nameControl = new FormControl<string | null>("name", Validators.required);
nameControl.events.subscribe((event) => {
  // process individual events
  console.log(event);
});

9. Coalescing by Default

Coalescing is now enabled by default for new apps using zone.js, reducing the number of change detection cycles and improving performance. Existing projects can opt-in by configuring the NgZone provider.

Example:

import { bootstrapApplication } from "@angular/platform-browser";
import { provideZoneChangeDetection } from "@angular/core";

bootstrapApplication(AppComponent, {
  providers: [provideZoneChangeDetection({ eventCoalescing: true })],
});

10. Event Replay

The event replay feature, introduced as a developer preview, ensures a seamless user experience for hybrid rendering by replaying events. This feature is enabled using withEventReplay().

Example:

import { bootstrapApplication } from "@angular/platform-browser";
import { provideClientHydration, withEventReplay } from "@angular/core";

bootstrapApplication(AppComponent, {
  providers: [provideClientHydration(withEventReplay())],
});

Conclusion

Angular 18 introduces several new features and enhancements aimed at improving performance, scalability, and developer experience. From zoneless applications and flexible routing to upgraded debugging tools and TypeScript 4.7 support, these updates make Angular a more powerful and efficient framework for building modern web applications.