@factory/eslint-plugin

An open-source ESLint plugin showcasing how agent-native organizations use custom lint rules to drive AI coding agents toward better results.

About This Project

This codebase is forked from what is used internally at Factory and has been altered to be more generic. We are sharing this as requested by the developer community and to showcase an example of what an agent-native organization does with custom lint rules to improve agent output quality.

All code in this repository is fully AI-generated.

To learn more about our approach:

• Using Linters to Direct Agents
• Agent Readiness

How to Use This Repository

Our recommendation is NOT to simply import this package. Instead, take the ideas from these rules and build your own set of custom lint rules tailored to your codebase, tech stack, and conventions.

We have included comprehensive markdown documentation for each rule (in rules/<rule-name>/README.md) that makes it easy for any AI agent to parse and adapt to your custom tech stack or framework.

Note: This repository is not planned to be actively maintained or updated. It is designed for sharing and inspiration only.

Available Configurations

Configuration Hierarchy

graph TD
    A[base] --> B[recommended]
    B --> C[frontend]
    B --> D[backend]

Factory Plugin Rules

This plugin includes custom rules that enforce code organization and best practices:

File Organization

• @factory/enum-file-organization - Enums must live in enums.ts files
• @factory/types-file-organization - Type definitions must live in types.ts files
• @factory/constants-file-organization - Constants must live in constants.ts files
• @factory/errors-file-organization - Error classes must live in errors.ts files
• @factory/test-utils-organization - Test utilities must live under test-utils/
• @factory/test-file-location - Test files must be colocated with source files

Naming & Exports

• @factory/filename-match-export - Filenames must match exported components/functions
• @factory/no-exported-function-expressions - Prefer function declarations for exports
• @factory/no-exported-string-union-types - Prefer enums over string union types

Testing

• @factory/require-test-files - TypeScript files must have corresponding test files
• @factory/require-tsx-test-stories-files - TSX files need test and story files
• @factory/jest-mock-absolute-paths - Jest mocks must use absolute paths
• @factory/jest-mock-require-actual - Jest mocks must include jest.requireActual()
• @factory/no-unstable-mock-module - Disallow unstable_mockModule

Logging

• @factory/structured-logging - Enforce structured logging patterns
• @factory/no-log-exception-with-throw - No logging exceptions before throwing

API Routes (Next.js/Express)

• @factory/require-route-middleware - Route files must use middleware
• @factory/require-v0-route-handle-middleware - v0 routes need specific middleware
• @factory/require-v0-strict-schemas - v0 routes need strict schema validation

React

• @factory/no-dynamic-styled-components - No dynamic styled-components
• @factory/no-plain-html-text-elements - No plain text in HTML elements
• @factory/no-use-effect-in-hooks - Restrict useEffect in custom hooks
• @factory/restrict-tsx-components - Enforce component patterns

Installation

npm install @factory/eslint-plugin eslint --save-dev

Quick Start

Create an .eslintrc.js file in your project root:

For TypeScript packages/libraries

module.exports = {
  root: true,
  plugins: ['@factory'],
  extends: ['plugin:@factory/recommended'],
};

For frontend applications (React/Vite)

module.exports = {
  root: true,
  plugins: ['@factory'],
  extends: ['plugin:@factory/frontend'],
};

For backend applications

module.exports = {
  root: true,
  plugins: ['@factory'],
  extends: ['plugin:@factory/backend'],
};

License

MIT