@e18e/eslint-plugin

The official e18e ESLint plugin for modernizing JavaScript/TypeScript code and improving performance.

Warning

This is an experimental, unpublished project for now. Once we have settled on the scope, we will publish it and announce it to start getting community feedback.

This plugin focuses on applying the e18e community's best practices and advise to JavaScript/TypeScript codebases.

Overview

There are a few categories of rules in this plugin:

• Modernization - New syntax and APIs which improve code readability and performance
• Module replacements - Community recommended alternatives to popular libraries, focused on performance and size
• Performance improvements - Patterns that can be optimized for better runtime performance

Each of these can be enabled individually, or you can use the recommended configuration to enable all rules.

Installation

npm install --save-dev @e18e/eslint-plugin

Usage

Add the plugin to your eslint.config.js:

import e18e from '@e18e/eslint-plugin';

export default [
  // Use the recommended configuration (includes all categories)
  e18e.configs.recommended,

  // Or use specific category configurations
  e18e.configs.modernization,
  e18e.configs.moduleReplacements,
  e18e.configs.performanceImprovements,

  // Or configure rules manually
  {
    plugins: {
      e18e
    },
    rules: {
      'e18e/prefer-array-at': 'error',
      'e18e/prefer-array-fill': 'error',
      'e18e/prefer-includes': 'error'
    }
  }
];

Rules

Modernization

Rule	Description	Recommended	Fixable
prefer-array-at	Prefer Array.prototype.at() over length-based indexing	✅	✅
prefer-array-fill	Prefer Array.prototype.fill() over Array.from() or map() with constant values	✅	✅
prefer-includes	Prefer .includes() over indexOf() comparisons for arrays and strings	✅	✅
prefer-array-to-reversed	Prefer Array.prototype.toReversed() over copying and reversing arrays	✅	✅
prefer-array-to-sorted	Prefer Array.prototype.toSorted() over copying and sorting arrays	✅	✅
prefer-array-to-spliced	Prefer Array.prototype.toSpliced() over copying and splicing arrays	✅	✅
prefer-exponentiation-operator	Prefer the exponentiation operator ** over Math.pow()	✅	✅
prefer-nullish-coalescing	Prefer nullish coalescing operator (?? and ??=) over verbose null checks	✅	✅
prefer-object-has-own	Prefer Object.hasOwn() over Object.prototype.hasOwnProperty.call() and obj.hasOwnProperty()	✅	✅
prefer-spread-syntax	Prefer spread syntax over Array.concat(), Object.assign({}, ...), and Function.apply()	✅	✅
prefer-url-canparse	Prefer URL.canParse() over try-catch blocks for URL validation	✅	💡

Fixable Legend:

• ✅ = Auto-fixable (changes applied automatically)
• 💡 = Has suggestions (requires user confirmation)
• ❌ = Not fixable

Module replacements

Rule	Description	Recommended	Fixable
ban-dependencies	Ban dependencies in favor of lighter alternatives	✅	❌

Performance improvements

No rules in this category yet.

License

MIT