eslint-plugin-ddd

ESLint plugin to enforce Domain-Driven Design (DDD) principles in your JavaScript and TypeScript projects.

Installation

``bash
pnpm add -D eslint-plugin-ddd
`

Usage

Add ddd to the plugins section of your .eslintrc configuration file:

`json
{
"plugins": ["ddd"]
}
`

Then configure the rules you want to use:

`json
{
"rules": {
"ddd/require-spec-file": "error"
}
}
`

$3

Alternatively, you can use the recommended configuration:

`json
{
"extends": ["plugin:ddd/recommended"]
}
`

Or the strict configuration:

`json
{
"extends": ["plugin:ddd/strict"]
}
`

Rules

$3

Enforces that every .js or .ts file containing logic has a corresponding .spec.js or .spec.ts file in the same directory.

Rule Details

This rule ensures test coverage by requiring spec files alongside implementation files that contain logic, promoting test-driven development and maintaining test organization.

What counts as "logic":
- Functions with implementations (not just type signatures)
- Classes with method implementations
- Executable code

Files automatically excluded (no logic):
- Type-only files (interfaces, types, enums)
- Constant-only files
- Simple re-export files

The rule automatically matches the file extension:
- .js files require .spec.js files
- .ts files require .spec.ts files

Examples of incorrect code:

`javascript
// src/user-service.js exists
// but src/user-service.spec.js does NOT exist
// ❌ ESLint will report an error
`

`typescript
// src/product-repository.ts exists
// but src/product-repository.spec.ts does NOT exist
// ❌ ESLint will report an error
`

Examples of correct code:

`javascript
// src/user-service.js exists with logic
// AND src/user-service.spec.js exists
// ✅ No error
`

`typescript
// src/product-repository.ts exists with logic
// AND src/product-repository.spec.ts exists
// ✅ No error
`

`javascript
// src/constants.js exists with ONLY constants (no logic)
// ✅ No spec file required
export const API_URL = 'https://api.example.com';
export const MAX_RETRIES = 3;
`

`typescript
// src/types.ts exists with ONLY types (no logic)
// ✅ No spec file required
export interface User {
id: string;
name: string;
}
`

Options

This rule accepts an options object with the following properties:

- excludePatterns (array of strings): Glob patterns to exclude from the spec file requirement

Default exclude patterns:
- */.spec.js - JavaScript spec files
- */.spec.ts - TypeScript spec files
- */.test.js - JavaScript test files
- */.test.ts - TypeScript test files
- **/index.js - JavaScript index files
- **/index.ts - TypeScript index files
- */.d.ts - TypeScript declaration files

Example configuration:

`json
{
"rules": {
"ddd/require-spec-file": ["error", {
"excludePatterns": [
"*/.spec.js",
"*/.spec.ts",
"*/.test.js",
"*/.test.ts",
"/config/",
"*/.config.js",
"*/.config.ts"
]
}]
}
}
`

Development

`bash


Install dependencies

pnpm install

Run tests

pnpm test

Run tests in watch mode

pnpm test:watch

Lint the code

pnpm lint
`

Releasing

This project uses release-it for automated releases.

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1. Copy the .env.example file to .env:
`bash
cp .env.example .env
`

2. Add your tokens to the .env file:
- GITHUB_TOKEN: GitHub Personal Access Token (generate here)
- NPM_TOKEN: NPM Access Token (generate here)

$3

`bash
pnpm release
``

This will:
- Run linting and tests
- Bump the version
- Create a git commit and tag
- Push to GitHub
- Create a GitHub release
- Publish to npm

License

MIT