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TypeScript Enforcement with ESLint ​

Ensure all TypeScript classes have architectural component decorators using ESLint.

Why Enforcement ​

Without enforcement, developers might forget decorators on new classes. This causes:

  • False negatives — Components missing from extraction
  • Incomplete architecture — Graph doesn't reflect reality
  • Silent failures — No feedback until extraction runs

ESLint catches missing decorators immediately in the IDE and during CI.

Installation ​

Install the conventions package (includes ESLint plugin):

bash
npm install --save-dev @living-architecture/riviere-extract-conventions

ESLint Configuration ​

Add the enforcement rule to your ESLint config (flat config format):

javascript
// eslint.config.mjs
import conventionsPlugin from '@living-architecture/riviere-extract-conventions/eslint-plugin'

export default [
  {
    files: ['src/domain/**/*.ts', 'src/api/**/*.ts'],
    plugins: {
      conventions: conventionsPlugin,
    },
    rules: {
      'conventions/require-component-decorator': 'error',
    },
  },
]

Scoping ​

Apply enforcement only to architectural code, not tests or utilities:

javascript
export default [
  // Enforce in domain and API layers
  {
    files: ['src/domain/**/*.ts', 'src/api/**/*.ts'],
    plugins: { conventions: conventionsPlugin },
    rules: { 'conventions/require-component-decorator': 'error' },
  },

  // No enforcement in tests
  {
    files: ['src/**/*.spec.ts', 'src/**/*.test.ts'],
    // conventions plugin not loaded
  },
]

Valid Decorators ​

The rule accepts these decorators as valid:

Container decorators:

  • @APIContainer
  • @DomainOpContainer
  • @EventHandlerContainer

Class-as-component decorators:

  • @UseCase
  • @Event
  • @UI

Method-level decorators:

  • @APIEndpoint
  • @DomainOp
  • @EventHandler

Other:

  • @Custom('type') — Custom component types
  • @Ignore — Explicitly excluded

Example Violations ​

Before (error):

typescript
class OrderController {
  // ❌ ESLint error: Class 'OrderController' must have a component decorator
  async createOrder(req: Request): Promise<Order> {
    // ...
  }
}

After (fixed):

typescript
import { APIContainer } from '@living-architecture/riviere-extract-conventions'

@APIContainer
class OrderController {
  // ✓ Valid
  async createOrder(req: Request): Promise<Order> {
    // ...
  }
}

CI Integration ​

Run ESLint in your CI pipeline:

yaml
# .github/workflows/ci.yml
- name: Lint
  run: npm run lint
json
// package.json
{
  "scripts": {
    "lint": "eslint src/"
  }
}

Ignored Elements ​

The rule ignores:

  • Functions (top-level functions, not methods)
  • Interfaces
  • Type aliases
  • Enums
  • Anonymous classes

Error Messages ​

text
Class 'OrderController' must have a component decorator.

Valid decorators:
  - @APIContainer, @DomainOpContainer, @EventHandlerContainer (containers)
  - @UseCase, @Event, @UI (class-as-component)
  - @Custom('type') (custom types)
  - @Ignore (explicit exclusion)

Import from: @living-architecture/riviere-extract-conventions

Enforcement Concept ​

This is the TypeScript implementation of architectural enforcement. Other languages use different tools:

Learn about Enforcement Principles →

See Also ​