feat!: Convert to ESM

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        eslint: [9, 8]
+        eslint: [9]
         node: [22.x, 21.x, 20.x, 18.x, "18.18.0"]
         include:
           - os: windows-latest

.github/workflows/release-please.yml

@@ -20,7 +20,10 @@ jobs:
           node-version: lts/*
           registry-url: https://registry.npmjs.org
         if: ${{ steps.release.outputs.release_created }}
-      - run: npm publish --provenance
+      - run: |
+          npm install
+          npm run build --if-present
+          npm publish --provenance
         env:
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
         if: ${{ steps.release.outputs.release_created }}

README.md

@@ -38,15 +38,6 @@ export default [
 ];
 ```
 
-If you are still using the deprecated `.eslintrc.js` file format for ESLint, you can extend the `plugin:markdown/recommended-legacy` config to enable the Markdown processor on all `.md` files:
-
-```js
-// .eslintrc.js
-module.exports = {
-    extends: "plugin:markdown/recommended-legacy"
-};
-```
-
 #### Advanced Configuration
 
 You can manually include the Markdown processor by setting the `processor` option in your configuration file for all `.md` files.
@@ -96,32 +87,6 @@ export default [
 ];
 ```
 
-In the deprecated `.eslintrc.js` format:
-
-```js
-// .eslintrc.js
-module.exports = {
-    // 1. Add the plugin.
-    plugins: ["markdown"],
-    overrides: [
-        {
-            // 2. Enable the Markdown processor for all .md files.
-            files: ["**/*.md"],
-            processor: "markdown/markdown"
-        },
-        {
-            // 3. Optionally, customize the configuration ESLint uses for ```js
-            // fenced code blocks inside .md files.
-            files: ["**/*.md/*.js"],
-            // ...
-            rules: {
-                // ...
-            }
-        }
-    ]
-};
-```
-
 #### Frequently-Disabled Rules
 
 Some rules that catch mistakes in regular code are less helpful in documentation.
@@ -163,30 +128,6 @@ export default [
 ];
 ```
 
-And in the deprecated `.eslintrc.js` format:
-
-```js
-// .eslintrc.js
-module.exports = {
-    plugins: ["markdown"],
-    overrides: [
-        {
-            files: ["**/*.md"],
-            processor: "markdown/markdown"
-        },
-        {
-            // 1. Target ```js code blocks in .md files.
-            files: ["**/*.md/*.js"],
-            rules: {
-                // 2. Disable other rules.
-                "no-console": "off",
-                "import/no-unresolved": "off"
-            }
-        }
-    ]
-};
-```
-
 #### Strict Mode
 
 `"use strict"` directives in every code block would be annoying.
@@ -205,8 +146,6 @@ The `markdown.configs.recommended` config disables these rules in Markdown files
 
 If you are using an `eslint.config.js` file, then you can run ESLint as usual and it will pick up file patterns in your config file. The `--ext` option is not available when using flat config.
 
-If you are using an `.eslintrc.*` file, then you can run ESLint as usual and it will pick up file extensions specified in `overrides[].files` patterns in config files.
-
 
 ### Autofixing
 

eslint.config.js

@@ -1,17 +1,14 @@
-"use strict";
+import globals from "globals";
+import eslintConfigESLint from "eslint-config-eslint";
+import eslintConfigESLintFormatting from "eslint-config-eslint/formatting";
+import markdown from "./src/index.js";
 
-module.exports = [
-    ...require("eslint-config-eslint/cjs").map(config => ({
-        ...config,
-        files: ["**/*.js"]
-    })),
-    {
-        ...require("eslint-config-eslint/formatting"),
-        files: ["**/*.js"]
-    },
+export default [
+    ...eslintConfigESLint,
+    eslintConfigESLintFormatting,
     {
         plugins: {
-            markdown: require(".")
+            markdown
         }
     },
     {
@@ -25,8 +22,11 @@ module.exports = [
         files: ["tests/**/*.js"],
         languageOptions: {
             globals: {
-                ...require("globals").mocha
+                ...globals.mocha
             }
+        },
+        rules: {
+            "no-underscore-dangle": "off"
         }
     },
     {

examples/react/eslint.config.js → examples/react/eslint.config.mjs

@@ -1,13 +1,13 @@
-"use strict";
 
-const markdown = require("eslint-plugin-markdown");
-const js = require("@eslint/js");
-const globals = require("globals");
+import js from "@eslint/js";
+import markdown from "../../src/index.js";
+import globals from "globals";
+import reactRecommended from "eslint-plugin-react/configs/recommended.js";
 
-module.exports = [
+export default [
     js.configs.recommended,
     ...markdown.configs.recommended,
-    require("eslint-plugin-react/configs/recommended"),
+    reactRecommended,
     {
         settings: {
             react: {

examples/typescript/eslint.config.js → examples/typescript/eslint.config.mjs

@@ -1,10 +1,8 @@
-"use strict";
+import js from "@eslint/js";
+import markdown from "../../src/index.js";
+import tseslint from "typescript-eslint";
 
-const markdown = require("eslint-plugin-markdown");
-const js = require("@eslint/js")
-const tseslint = require("typescript-eslint");
-
-module.exports = tseslint.config(
+export default tseslint.config(
     js.configs.recommended,
     ...markdown.configs.recommended,
     {

package.json

@@ -7,6 +7,16 @@
     "name": "Brandon Mills",
     "url": "https://github.com/btmills"
   },
+  "type": "module",
+  "main": "src/index.js",
+  "exports": {
+    "import": {
+      "default": "./src/index.js"
+    }
+  },
+  "files": [
+    "src"
+  ],
   "repository": "eslint/eslint-plugin-markdown",
   "bugs": {
     "url": "https://github.com/eslint/eslint-plugin-markdown/issues"
@@ -21,35 +31,30 @@
   ],
   "scripts": {
     "lint": "eslint .",
-    "prepare": "node ./npm-prepare.js",
+    "prepare": "node ./npm-prepare.cjs",
     "release:generate:latest": "eslint-generate-release",
     "release:generate:alpha": "eslint-generate-prerelease alpha",
     "release:generate:beta": "eslint-generate-prerelease beta",
     "release:generate:rc": "eslint-generate-prerelease rc",
     "release:publish": "eslint-publish-release",
-    "test": "nyc _mocha -- -c tests/{examples,lib}/**/*.js --timeout 30000"
+    "test": "c8 mocha \"tests/**/*.test.js\" --timeout 30000"
   },
-  "main": "index.js",
-  "files": [
-    "index.js",
-    "lib/index.js",
-    "lib/processor.js"
-  ],
   "devDependencies": {
+    "@eslint/core": "^0.2.0",
     "@eslint/js": "^9.4.0",
-    "chai": "^4.2.0",
+    "c8": "^10.1.2",
+    "chai": "^5.1.1",
     "eslint": "^9.4.0",
     "eslint-config-eslint": "^11.0.0",
     "eslint-release": "^3.1.2",
     "globals": "^15.1.0",
-    "mocha": "^6.2.2",
-    "nyc": "^14.1.1"
+    "mocha": "^10.6.0"
   },
   "dependencies": {
-    "mdast-util-from-markdown": "^0.8.5"
+    "mdast-util-from-markdown": "^2.0.1"
   },
   "peerDependencies": {
-    "eslint": ">=8"
+    "eslint": ">=9"
   },
   "engines": {
     "node": "^18.18.0 || ^20.9.0 || >=21.1.0"

release-please-config.json

@@ -4,8 +4,8 @@
       "release-type": "node",
       "pull-request-title-pattern": "chore: release ${version} 🚀",
       "extra-files": [
-        "lib/index.js",
-        "lib/processor.js"
+        "src/index.js",
+        "src/processor.js"
       ]
     }
   }

lib/index.js → src/index.js

@@ -3,9 +3,7 @@
  * @author Brandon Mills
  */
 
-"use strict";
-
-const processor = require("./processor");
+import { processor } from "./processor.js";
 
 const rulesConfig = {
 
@@ -100,4 +98,4 @@ plugin.configs.recommended = [
     }
 ];
 
-module.exports = plugin;
+export default plugin;

lib/processor.js → src/processor.js

@@ -25,9 +25,7 @@
  * @typedef {ASTNode & BlockBase} Block
  */
 
-"use strict";
-
-const parse = require("mdast-util-from-markdown");
+import { fromMarkdown } from "mdast-util-from-markdown";
 
 const UNSATISFIABLE_RULES = new Set([
     "eol-last", // The Markdown parser strips trailing newlines in code fences
@@ -248,7 +246,7 @@ const languageToFileExtension = {
  * @returns {Array<{ filename: string, text: string }>} Source code blocks to lint.
  */
 function preprocess(text, filename) {
-    const ast = parse(text);
+    const ast = fromMarkdown(text);
     const blocks = [];
 
     blocksCache.set(filename, blocks);
@@ -409,7 +407,7 @@ function postprocess(messages, filename) {
     });
 }
 
-module.exports = {
+export const processor = {
     meta: {
         name: "eslint-plugin-markdown/markdown",
         version: "5.1.0" // x-release-please-version

tests/examples/all.js → tests/examples/all.test.js

@@ -1,10 +1,13 @@
-"use strict";
-
-const assert = require("chai").assert;
-const fs = require("fs");
-const path = require("path");
-const semver = require("semver");
+import { assert } from "chai";
+import fs from "node:fs";
+import path from "node:path";
+import semver from "semver";
+import { createRequire } from "node:module";
+import { fileURLToPath } from "node:url";
 
+const require = createRequire(import.meta.url);
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
 const examplesDir = path.resolve(__dirname, "../../examples/");
 const examples = fs.readdirSync(examplesDir)
     .filter(exampleDir => fs.statSync(path.join(examplesDir, exampleDir)).isDirectory())
@@ -14,7 +17,7 @@ for (const example of examples) {
     const cwd = path.join(examplesDir, example);
 
     // The plugin officially supports ESLint as early as v6, but the examples
-    // use ESLint v7, which has a higher minimum Node.js version than does v6.
+    // use ESLint v8, which has a higher minimum Node.js version than does v6.
     // Only exercise the example if the running Node.js version satisfies the
     // minimum version constraint. In CI, this will skip these tests in Node.js
     // v8 and run them on all other Node.js versions.

tests/fixtures/eslint.config.js

@@ -1,7 +1,7 @@
-const markdown = require("../../");
-const globals = require("globals");
+import markdown from "../../src/index.js";
+import globals from "globals";
 
-module.exports = [
+export default [
     {
         plugins: {
             markdown

tests/fixtures/recommended.js

@@ -1,7 +1,7 @@
-const markdown = require("../../");
-const js = require("@eslint/js")
+import markdown from "../../src/index.js";
+import js from "@eslint/js";
 
-module.exports = [
+export default [
     js.configs.recommended,
     ...markdown.configs.recommended,
     {