Angular

Angular

Angular is a platform for building mobile and desktop web applications. Angular 19 (2025) has completely reinvented itself with Signals, Standalone Components, and optional Zone.js.

When to Use

• Enterprise Applications: Strict structure, opinionated, and "batteries-included" (Router, Forms, HTTP).
• Large Teams: TypeScript and strict patterns make it easier for large teams to collaborate.
• Long-term Maintenance: Angular's update story is excellent (CLI automates migrations).

Quick Start (Signals)

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

@Component({
  selector: "app-counter",
  standalone: true,
  template: `
    <p>Count: {{ count() }}</​p>
    <p>Double: {{ double() }}</​p>
    <button (click)="increment()">Increment</​button>
  `,
})
export class CounterComponent {
  count = signal(0);
  double = computed(() => this.count() * 2);

  increment() {
    this.count.update((c) => c + 1);
  }
}

Core Concepts

Signals

The new reactivity primitive. Fine-grained reactivity that allows Angular to drop Zone.js and only update the exact text node that changed.

Standalone Components

No more NgModule. Components import their dependencies directly.

Deferrable Views (@defer)

Built-in syntax to lazy-load parts of templates.

@defer (on viewport) {
<heavy-chart />
} @placeholder {
<p>Loading...</​p>
}

Best Practices (2025)

Do:

• Use Signals: Prefer signal() over BehaviorSubject for component state.
• Use inject(): Prefer the inject(Service) function over constructor dependency injection.
• Go Zoneless: Enable provideExperimentalZonelessChangeDetection() for better performance.

Don't:

• Don't use NgModule: Unless maintaining legacy code.
• Don't use CommonModule: Use new control flow syntax (@if, @for) instead of *ngIf, *ngFor.

References

• Angular Documentation