eslint-plugin-simple-header

1.2.2 verified Mon Apr 27 auth: no javascript

ESLint plugin for enforcing and auto-fixing license headers in source files. Current stable version is 1.2.2. It requires ESLint >=8.41.0 and ships TypeScript type definitions. Designed as a lightweight alternative to eslint-plugin-header with support for template variables (year, author, etc.), multiple comment syntaxes (block, line), and configurable decoration. It uses ESM-only exports and has a flat config-first API.

Common errors

error Cannot find module 'eslint-plugin-simple-header' ↓

cause Module is ESM-only and not transpiled for CommonJS; your project uses require().

fix

Switch to import or set "type": "module" in package.json.

error Configuration for rule "simple-header/header" is invalid: value must be an array ↓

cause Rule entry is missing array brackets in flat config.

fix

Use "simple-header/header": ["error", { ... }] instead of "simple-header/header": { ... }.

error Cannot read properties of undefined (reading 'year') ↓

cause Missing templates definition for year variable used in header text.

fix

Add templates: { year: { pattern: "\\d{4}", default: "2023" } } to the rule options.

Warnings

breaking v1.x removes support for legacy ESLint config format (no use .eslintrc) ↓

fix Use flat config (eslint.config.js) with plugins object as shown in docs.

breaking ESM-only module, import fails with require() ↓

fix Use import instead of require; configure package.json with "type": "module" if needed.

deprecated The old syntax for templates used an array [pattern, default] is deprecated in favor of object {pattern, default} ↓

fix Use object syntax: { pattern: '...', default: '...' } instead of array.

gotcha Default year template matches only 4-digit years but does not validate realistic year range ↓

fix Override template pattern if you need custom year validation.

gotcha If no files option is provided, rule applies to all files; may cause linting errors on non-code files ↓

fix Specify files pattern (e.g., ['**/*.js']) to limit scope.

Install

npm install eslint-plugin-simple-header

yarn add eslint-plugin-simple-header

pnpm add eslint-plugin-simple-header

Imports

default

wrong

const simpleHeader = require('eslint-plugin-simple-header')

correct

import simpleHeader from 'eslint-plugin-simple-header'

ESM-only; CommonJS require() will fail since package type is module.

rules

wrong

const { rules } = require('eslint-plugin-simple-header')

correct

const { rules } = await import('eslint-plugin-simple-header')

Named export only accessible via dynamic import due to ESM.

simple-header/header
wrong
```
"header": ["error", { ... }]
```
correct
```
"simple-header/header": ["error", { ... }]
```
Rule key must be prefixed with plugin name in flat config.

Quickstart

ESLint flat config with simple-header plugin, using template variables for year and author.

import simpleHeader from "eslint-plugin-simple-header";

export default [
  {
    plugins: {
      "simple-header": simpleHeader,
    },
    rules: {
      "simple-header/header": ["error", {
        text: [
          "Copyright (c) {year} {author}",
          "SPDX-License-Identifier: MIT",
        ],
        templates: {
          year: { pattern: "\\d{4}", default: new Date().getFullYear().toString() },
          author: { pattern: ".*", default: "John Doe" },
        },
      }],
    },
  },
];