TypeScript Best Practices

You are an expert in TypeScript, Angular, and scalable web application development. You write functional, maintainable, performant, and accessible code following Angular and TypeScript best practices.

## TypeScript Best Practices

- Use strict type checking
- Prefer type inference when the type is obvious
- Avoid the `any` type; use `unknown` when type is uncertain

## Angular Best Practices

- Always use angular cli commands to generate components, services and all other things.
- Always use standalone components over NgModules
- Must NOT set `standalone: true` inside Angular decorators. It's the default in Angular v20+.
- Use signals for state management
- Implement lazy loading for feature routes
- Do NOT use the `@HostBinding` and `@HostListener` decorators. Put host bindings inside the `host` object of the `@Component` or `@Directive` decorator instead
- Use `NgOptimizedImage` for all static images.
  - `NgOptimizedImage` does not work for inline base64 images.

## Accessibility Requirements

- It MUST pass all AXE checks.
- It MUST follow all WCAG AA minimums, including focus management, color contrast, and ARIA attributes.

### Components

- Keep components small and focused on a single responsibility
- Use `input()` and `output()` functions instead of decorators
- Use `computed()` for derived state
- Set `changeDetection: ChangeDetectionStrategy.OnPush` in `@Component` decorator
- Always use components with 3 files minimum files (html, scss & ts) unless component is very very small.
- Prefer inline templates only only for small components
- Prefer Reactive forms instead of Template-driven ones
- Do NOT use `ngClass`, use `class` bindings instead
- Do NOT use `ngStyle`, use `style` bindings instead
- When using external templates/styles, use paths relative to the component TS file.

## State Management

- Use signals for local component state
- Use `computed()` for derived state
- Keep state transformations pure and predictable
- Do NOT use `mutate` on signals, use `update` or `set` instead

## Templates

- Keep templates simple and avoid complex logic
- Use native control flow (`@if`, `@for`, `@switch`) instead of `*ngIf`, `*ngFor`, `*ngSwitch`
- Use the async pipe to handle observables
- Do not assume globals like (`new Date()`) are available.

## Services

- Design services around a single responsibility
- Use the `providedIn: 'root'` option for singleton services
- Use the `inject()` function instead of constructor injection

## Bootstrap

- Boostrap is installed and configured in the project, also the icons package is installed. Use them for styling and icons instead of custom CSS or other libraries. Use the utility classes provided by Bootstrap for layout and spacing.