eslint-plugin-lit

2.2.1 verified Sat Apr 25 auth: no javascript

ESLint plugin for Lit (lit-html / LitElement) providing 23+ lint rules covering attribute names, binding positions, lifecycle super calls, legacy syntax, and more. Stable version 2.2.1, released as needed with minor updates. ESM-only since v2.0.0, requires Node >= 18 and ESLint >= 8. Supports flat config and has recommended shareable config. Differentiated from general ESLint rules by targeting Lit-specific constructs like template literals and LitElement classes, with TypeScript type definitions included.

Common errors

error Error [ERR_REQUIRE_ESM]: require() of ES Module not supported ↓

cause Using require() with eslint-plugin-lit >=2.0.0 which is ESM-only.

fix

Change to import statement or use dynamic import: const plugin = await import('eslint-plugin-lit');

error ESLint configuration error: Cannot find module 'eslint-plugin-lit' ↓

cause Plugin not installed or not in node_modules.

fix

Run npm install eslint-plugin-lit --save-dev

error TypeError: configs is not iterable ↓

cause Incorrect import or usage of configs in flat config.

fix

Ensure you use import { configs } from 'eslint-plugin-lit' and spread it correctly: export default [configs['flat/recommended'], ...]

Warnings

breaking v2.0.0 migrated to ESM-only; require() breaks. ↓

fix Use import statements or dynamic import() in CommonJS files.

deprecated The .eslintrc config format plugin:lit/recommended is deprecated; use flat config (configs['flat/recommended']). ↓

fix Switch to eslint.config.js with import { configs } from 'eslint-plugin-lit'.

gotcha Default import of the plugin is deprecated; prefer named exports (configs, rules). ↓

fix Use import { configs } from 'eslint-plugin-lit' instead of default import.

breaking Node < 18 is no longer supported; engine requirement was raised. ↓

fix Upgrade Node.js to version 18 or higher.

gotcha Some rules (e.g., no-legacy-template-syntax) may require Lit v2+; check rule docs. ↓

fix Ensure your project uses Lit v2 or later if enabling such rules.

Install

npm install eslint-plugin-lit

yarn add eslint-plugin-lit

pnpm add eslint-plugin-lit

Imports

configs

wrong

const { configs } = require('eslint-plugin-lit')

correct

import { configs } from 'eslint-plugin-lit'

ESM-only since v2.0.0; require() will fail. Use dynamic import() if needed.

rules
wrong
```
import eslintPluginLit from 'eslint-plugin-lit'
```
correct
```
import { rules } from 'eslint-plugin-lit'
```
rules is a named export, not default. Default export exists but is deprecated in favor of named configs.
default import
wrong
```
const eslintPluginLit = require('eslint-plugin-lit')
```
correct
```
import eslintPluginLit from 'eslint-plugin-lit'
```
Default export is the plugin object but named exports (configs, rules) are preferred.

Quickstart

Flat config usage with recommended rules and a custom rule override.

// eslint.config.js
import { configs } from 'eslint-plugin-lit';

export default [
  configs['flat/recommended'],
  {
    files: ['**/*.js', '**/*.ts'],
    rules: {
      'lit/no-legacy-template-syntax': 'error',
    },
  },
];