Angular 20 Skill

Rules

Component Architecture

MUST use standalone components:

• All new components MUST be standalone
• Components MUST use standalone: true in decorator
• Components MUST explicitly import dependencies in imports array

MUST NOT use NgModule-based components in new code:

• NgModule declarations are forbidden for new components

State Management

MUST use Signals for local state:

• Use signal() for component-level reactive state
• Use computed() for derived state
• Use effect() for side effects

MUST use @ngrx/signals for global state:

• Centralized application state MUST use @ngrx/signals
• MUST NOT use custom state management solutions

Routing

MUST use lazy-loaded routes for large modules:

• Feature modules MUST be lazy loaded
• Use loadChildren or loadComponent for routing

MUST implement prefetching strategies:

• Configure preloading strategy for performance optimization

HTTP & API

MUST use HttpClient with typed responses:

• All HTTP calls MUST specify response types
• API services MUST centralize HTTP logic
• Error handling MUST be implemented for all HTTP calls

Testing

MUST include unit tests:

• Use Jasmine/Karma or Jest for unit testing
• Components MUST have corresponding spec files

MUST include E2E tests for critical flows:

• Use Playwright for E2E testing

Performance

MUST use AOT compilation for production:

• Production builds MUST use ng build with AOT

MUST use OnPush change detection where applicable:

• Components with Signals SHOULD use ChangeDetectionStrategy.OnPush

Accessibility

MUST enforce accessibility (a11y) guidelines:

• Templates MUST follow WCAG standards
• Interactive elements MUST be keyboard accessible

Build & Deployment

MUST use Angular CLI for builds:

• Use ng build to create production artifacts

MUST configure environment-specific settings:

• Separate configurations for development, staging, and production

Context

Purpose

This skill provides structured guidance and best practices for Angular 20 development, including typical workflows, common patterns, quality standards, and example templates.

Angular 20 Core Concepts

• Angular 20 features & changes
• TypeScript-first architecture
• Standalone components
• Signals and reactivity
• Composition API
• Angular CLI workflows

When to Use This Skill

Use this skill when:

• Developing Angular 20 applications
• Setting up new Angular projects
• Implementing components, routing, state management
• Optimizing performance
• Writing tests
• Deploying Angular applications

Key Tasks & Workflows

1) Create a new Angular 20 app

Use Angular CLI to bootstrap projects:

ng new your-app --routing --style=scss

2) Component & Template Patterns

• Use standalone components where possible
• Keep templates clean & concise
• Enforce accessibility (a11y) guidelines

3) Routing & Navigation

• Setup RouterModule with routes
• Use lazy-loaded routes for large modules
• Implement prefetching strategies for performance

4) State & Reactivity

• Prefer Signals for local state
• Consider @ngrx/signals for global state
• Manage effects/rx workflows carefully

5) HTTP & REST

• Use HttpClient with typed responses
• Centralize API service layer with error handling

6) Testing

• Unit test with Jasmine/Karma or Jest
• E2E tests with Playwright

7) Performance

• Use AOT compilation
• Optimize bundle with ng build
• Use OnPush change detection where applicable

8) Deployment

• Build artifacts: ng build
• Serve with static hosts / CDNs
• Configure environment-specific settings

📌 Examples & Code Snippets

Example Standalone Component

import { Component } from '@angular/core';
import { CommonModule } from '@angular/common';

@Component({
  selector: 'app-example',
  standalone: true,
  imports: [CommonModule],
  template: `
    @if (showContent()) {
      <div>Content here</div>
    }
  `
})
export class ExampleComponent {
  showContent = signal(true);
}

Example Reactive Form

import { Component, inject } from '@angular/core';
import { FormBuilder, ReactiveFormsModule, Validators } from '@angular/forms';

@Component({
  selector: 'app-form',
  standalone: true,
  imports: [ReactiveFormsModule],
  template: `
    <form [formGroup]="form">
      <input formControlName="name" />
    </form>
  `
})
export class FormComponent {
  private fb = inject(FormBuilder);
  
  form = this.fb.group({
    name: ['', Validators.required]
  });
}

Example API Service

import { Injectable, inject } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({ providedIn: 'root' })
export class ApiService {
  private http = inject(HttpClient);
  
  getData(): Observable<any[]> {
    return this.http.get<any[]>('/api/data');
  }
}

Refer to official Angular docs and community standards for evolving best practices.

---

📂 Installation Path

🎯 Project-specific skill

.github/skills/angular-20/SKILL.md

🎯 Personal global skill

~/.github/skills/angular-20/SKILL.md

💡 Copilot will automatically load this skill based on your prompt content.