eslint-config-yenz

eslint-config-yenz

An opinionated ESLint configuration for TypeScript projects. Built for ESLint 9 with flat config support.

What's Included

This config bundles and configures the following plugins:

• @eslint/js — ESLint recommended rules
• @typescript-eslint — TypeScript-specific linting with type-checked rules
• @stylistic/eslint-plugin — Code formatting rules
• eslint-plugin-import — Import organization and validation
• eslint-plugin-jest — Jest testing best practices
• eslint-plugin-perfectionist — Code organization (selectively disabled)
• eslint-plugin-yenz — Custom rules

Installation

npm install eslint-config-yenz --save-dev

Usage

Create an eslint.config.mjs in your project root:

import yenz from 'eslint-config-yenz'

export default [
  {
    files: ['**/*.ts', '**/*.tsx'],
    ...yenz,
  },
]

Or import individual parts directly:

import { plugins, rules, languageOptions } from 'eslint-config-yenz'

export default [
  {
    files: ['**/*.ts', '**/*.tsx'],
    plugins,
    languageOptions,
    rules,
  },
]

Combining with Other Configs

A more realistic setup with ignore patterns, rule overrides, and additional plugins:

import yenz from 'eslint-config-yenz'
// Example: adding another plugin alongside yenz (not required)
import react from 'eslint-plugin-react'

export default [
  {
    ignores: ['dist/**', 'node_modules/**', 'coverage/**'],
  },
  {
    files: ['**/*.ts', '**/*.tsx'],
    ...yenz,
    // Example: merging in additional plugins
    plugins: {
      ...yenz.plugins,
      react,
    },
    // Example: extending language options
    languageOptions: {
      ...yenz.languageOptions,
      parserOptions: {
        ...yenz.languageOptions.parserOptions,
        ecmaFeatures: { jsx: true },
      },
    },
    rules: {
      ...yenz.rules,
      // Example: relaxing the included rules for your project
      '@typescript-eslint/explicit-function-return-type': 'warn',
      'no-magic-numbers': 'off',
    },
  },
]

Selective Imports

You can import individual parts for more granular control:

import { plugins, rules, languageOptions } from 'eslint-config-yenz'

export default [
  {
    files: ['**/*.ts'],
    plugins: {
      ...plugins,
    },
    // Example: pointing to a specific tsconfig
    languageOptions: {
      ...languageOptions,
      parserOptions: {
        ...languageOptions.parserOptions,
        project: './tsconfig.app.json',
      },
    },
    // Example: overriding specific rules
    rules: {
      ...rules,
      'no-console': 'off',
      'semi': ['error', 'always'],
    },
  },
]

Adding Jest Support for Test Files

The config includes the Jest plugin but you need to apply it to your test files:

import yenz from 'eslint-config-yenz'
import jest from 'eslint-plugin-jest'

export default [
  {
    files: ['**/*.ts', '**/*.tsx'],
    ...yenz,
  },
  {
    files: ['**/*.test.ts', '**/*.spec.ts'],
    ...yenz,
    ...jest.configs['flat/recommended'],
    rules: {
      ...yenz.rules,
      ...jest.configs['flat/recommended'].rules,
      // Example: relaxing strict rules for test files
      '@typescript-eslint/no-unsafe-assignment': 'off',
      'no-magic-numbers': 'off',
    },
  },
]

Style Guide

This config enforces the following conventions:

Rule	Setting
Quotes	Single
Semicolons	Never
Indentation	2 spaces
Brace style	Stroustrup
Line endings	Unix (LF)
Trailing newline	Required
Console	Only console.error and console.warn
Magic numbers	Restricted (allows -1 through 10, 60 (for seconds/minutes), 100)
Import order	Alphabetized with groups: builtin, external, internal, parent, sibling, index
Import spacing	2 blank lines after imports

TypeScript Rules

• Type-checked rules enabled via @typescript-eslint/recommended-type-checked
• Explicit function return types required
• Unsafe operations (any usage) produce warnings
• Unused variables are errors (prefix with _ to ignore)
• Unnecessary conditions flagged as errors

Release Procedure

1. Open a new branch for your work.
2. Make all changes in that branch.
3. Add code samples in test/ that intentionally fail your new or updated config to confirm they are caught.
4. Commit and push your changes, then open a PR.
5. Bump to a pre-release version and publish a beta:

   yarn version --pre[major|minor|patch] --preid beta
   npm publish --tag beta                # or alpha, rc

   Users can test it with:

   yarn add eslint-config-yenz@beta   # or @alpha, @rc

6. After review, merge your branch into main.
7. Open a version bump PR against main and merge it in.
8. Publish the stable release from main:

   yarn version --[major|minor|patch]
   npm publish

Why yarn version + npm publish? yarn version handles the version bump, git tag, and commit. We use npm publish for the actual publish because yarn publish redundantly prompts for a new version even when one was already set.