@sethlivingston/eslint-plugin-typescript-narrows

Opinionated ESLint plugin for TypeScript

Install

npm install --save-dev @sethlivingston/eslint-plugin-typescript-narrows

Quick Start

import tsnarrows from "@sethlivingston/eslint-plugin-typescript-narrows";

export default [
  ...tsnarrows.configs.strict,
  ...tsnarrows.configs.test,
  ...tsnarrows.configs.tooling,
];

Use the presets together in that order:

• strict for ordinary source files
• test for *.test.*, *.spec.*, __tests__/, and tests/ helpers
• tooling for config entrypoints such as eslint.config.ts, vite.config.ts, vitest.config.ts, and tsup.config.ts

Presets

| Preset | Intended files | Notes | | ------ | -------------- | ----- | | configs.strict | Source code | Main strict preset for production and library code | | configs.test | Test files and test helpers | Relaxes ceremony-heavy rules like explicit return types, readonly parameter types, and require-await, while keeping safety rules like no-floating-promises | | configs.tooling | Tooling and config entrypoints | Keeps strict behavior but turns off import/no-default-export for conventional config files |

The strict preset also allows build-time injected constants that follow ^__[_A-Z0-9]+__$, including declared globals and object-literal define maps.

What's Included

• 20+ typescript-eslint rules configured to opinionated defaults
• 3 ESLint core rules
• 3 import-x rules
• 2 custom rules (ban-enums, ban-barrel-files)

30+ rules total, enforcing over half of the project's opinions (some rules cover multiple opinions).

Custom Rules

| Rule | Description | Auto-fixable | | ------------------------------------- | ------------------------------------------------------------------------ | :----------: | | typescript-narrows/ban-enums | Bans enum and const enum declarations in favor of as const objects | No | | typescript-narrows/ban-barrel-files | Bans barrel files (index.ts re-export files) | No |

Companion Plugin

This plugin pairs with The TypeScript Narrows Claude Plugin, which provides all opinions as structured guidance for AI-assisted development. The skill covers the opinions that cannot be enforced through lint rules.

License

MIT