/angular-style-guide

name: angular-style-guide
description: Naming conventions, file structure, and coding standards for Angular projects. Use for Angular-specific naming and organization; defer language-only TypeScript naming questions.
metadata:
  triggers:
    keywords:
    - angular style
    - naming convention
    - file structure
    - angular-style-guide

Angular Style Guide

**Priority: P0 (CRITICAL)**

Principles

• **Single Responsibility**: 1 component/service per file. Functions < 75 lines.
• **Size Limits**: Files < **400 lines**. Refactor if larger.
• **Strict Naming**: **kebab-case** with **type suffix** (e.g., **hero-list.component.ts**, **auth.service.ts**, **user.pipe.ts**, **app.routes.ts**).
• **Barrels**: `index.ts` for public APIs only. No deep barrel imports within same feature — import directly. Wrong barrel placement breaks **tree-shaking**.
• **LIFT**: **Locate** code quickly, **Identify files** by name, keep **Flattest structure** possible, **Try** to be **DRY**.

Naming Standards

• **Files**: `kebab-case.type.ts`
• **Classes**: **PascalCase** + **type suffix** (**HeroListComponent**, **AuthService**)
• **Directives**: **camelCase** selector with **app prefix** (e.g., `appHighlight`)
• **Pipes**: **camelCase** name (e.g., `truncate`)
• **Services**: **PascalCase** + **Service** suffix (`HeroService`)
• **Interfaces**: No — do not use `IUser`/`IHero`. Name as nouns: `User`, `Hero`. The I-prefix is not recommended by Angular style guide.

Folder Structure

• **Core**: `src/app/core/` (**singletons** and global state).
• **Shared**: `src/app/shared/` (**reusable UI** and pipes).
• **Features**: `src/app/features/` (**lazy-loaded**). Folder **depth ≤ 3 levels** — no deeper nesting.

Anti-Patterns

• **No logic in templates**: Move to component class or `computed()` signal.
• **No deep nesting**: Keep folder depth ≤3 levels.
• **No I-prefix on interfaces**: Name interfaces `User`, not `IUser`.

References

• [Naming Conventions](references/naming-convention.md)

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

• app prefix,appHighlight,appFocusTrap
• Flattest structure
• do not use I,avoid the I-prefix,no I-prefix,do not prefix,No. Do not