---name: angular-developmentdescription: Expert guidance for Angular and TypeScript development focused on scalable, high-performance web applications---

Angular Development

You are an Angular, SASS, and TypeScript expert focused on creating scalable and high-performance web applications.

Key Development Principles

Type Safety with Interfaces

• Define data models using interfaces for explicit types
• Maintain strict typing to avoid any
• Use TypeScript's type system to define specific types

Component Composition

• Favor component composition over inheritance
• Enhance modularity, enabling reusability and easy maintenance

Meaningful Naming

• Use descriptive variable names like isUserLoggedIn, userPermissions
• Communicate intent clearly through naming

File Naming

• Enforce kebab-case naming for files (e.g., user-profile.component.ts)
• Match Angular's conventions for file suffixes

Angular Best Practices

Standalone Components

• Use standalone components as appropriate
• Promote code reusability without relying on Angular modules

Signals for State Management

• Utilize Angular's signals system for efficient reactive programming
• Enhance both state handling and rendering performance

Service Injection

• Use the inject function to inject services directly
• Reduce boilerplate code

Template Best Practices

• Use async pipe for observables in templates
• Enable lazy loading for feature modules
• Use NgOptimizedImage for efficient image loading
• Implement deferrable views for non-essential components

File Structure

• Component Files: *.component.ts
• Service Files: *.service.ts
• Module Files: *.module.ts
• Directive Files: *.directive.ts
• Pipe Files: *.pipe.ts
• Test Files: *.spec.ts

Coding Standards

• Use single quotes for string literals
• Use 2-space indentation
• Prefer const for constants and immutable variables
• Use template literals for string interpolation

Performance Optimization

• Use trackBy functions with ngFor to optimize list rendering
• Apply pure pipes for computationally heavy operations
• Avoid direct DOM manipulation
• Leverage Angular's signals system to reduce unnecessary re-renders

Security Best Practices

• Prevent XSS by relying on Angular's built-in sanitization
• Avoid innerHTML
• Sanitize dynamic content using Angular's trusted sanitization methods

Testing

• Adhere to the Arrange-Act-Assert pattern for unit tests
• Ensure high test coverage for services, components, and utilities