feat: support new config system

README.md

@@ -23,7 +23,7 @@ Install the plugin alongside ESLint v6 or greater:
 npm install --save-dev eslint eslint-plugin-markdown
 ```
 
-### Configuring
+### Configuring (legacy: `.eslintrc*`)
 
 Extending the `plugin:markdown/recommended` config will enable the Markdown processor on all `.md` files:
 
@@ -201,6 +201,92 @@ module.exports = {
 };
 ```
 
+### Configuring (new: `eslint.config.js`)
+
+From [`v8.21.0`](https://github.com/eslint/eslint/releases/tag/v8.21.0), eslint announced a new config system.
+In the new system, `.eslintrc*` is no longer used. `eslint.config.js` would be the default config file name.
+
+And from [`v8.23.0`](https://github.com/eslint/eslint/releases/tag/v8.23.0), eslint CLI starts to look up `eslint.config.js`.
+**So, if your eslint is `>=8.23.0`, you're 100% ready to use the new config system.**
+
+You might want to check out the official blog posts,
+
+- <https://eslint.org/blog/2022/08/new-config-system-part-1/>
+- <https://eslint.org/blog/2022/08/new-config-system-part-2/>
+- <https://eslint.org/blog/2022/08/new-config-system-part-3/>
+
+and the [official docs](https://eslint.org/docs/latest/user-guide/configuring/configuration-files-new).
+
+### Shareable config
+
+Extending the the `recommended` config will enable the Markdown processor on all .md files.
+
+```ts
+import markdown from 'eslint-plugin-markdown/recommended' // <== trailing '/recommended'
+
+export default [
+  // --- snip ---
+  ...markdown,
+  // --- snip ---
+]
+```
+
+### Plugin
+
+The `recommended` shareable config might not fit to you.
+Then use plugin object directly instead of the config object.
+Unlike `eslint-plugin-markdown/recommended`, the default export of `eslint-plugin-markdown` is a plugin object.
+
+If your `eslint.config.js` is ESM, you can import and use the plugin like this.
+
+<!-- eslint-skip -->
+```js
+import markdown from "eslint-plugin-markdown"
+
+export default [
+    {
+        files: ["*.md"],
+        plugins: {
+            markdown
+        },
+        processor: "markdown/markdown"
+    },
+    {
+        files: ["**/*.md/*.js"],
+        plugins: {
+            markdown
+        },
+        languageOptions: {
+            parserOptions: {
+                // ...
+            },
+        },
+        // ...
+        rules: {
+            // ...
+        },
+    },
+]
+```
+
+If your `eslint.config.js` is CJS, you can import and use the plugin like this.
+
+<!-- eslint-skip -->
+```js
+const markdown = require("eslint-plugin-markdown/new"); // <== trailing '/new'
+
+module.exports = [
+    {
+    // ... others are omitted for brevity
+        plugins: {
+            markdown
+        }
+    }
+];
+```
+
+For more usage tips, refer to [Advanced Configuration](#advanced-configuration), [Frequently-Disabled Rules](#frequently-disabled-rules), [strict-mode](#strict-mode), [Unsatisfiable Rules](#unsatisfiable-rules), and [Migrating from `eslint-plugin-markdown` v1](#migrating-from-eslint-plugin-markdown-v1). Those usage details are different as they are based on the legacy config system, but the concepts behind of it is same between the legacy and the new. Thus if you already have prerequisite understanding of the new config system, you will be able to know how to adapt it to the new config system.
+
 ### Running
 
 #### ESLint v7

index.js

@@ -1,8 +1,7 @@
-/**
- * @fileoverview Exports the processor.
- * @author Brandon Mills
- */
-
 "use strict";
 
-module.exports = require("./lib");
+const processor = require("./lib/processor");
+
+module.exports = {
+    processor
+};

legacy.js

@@ -0,0 +1,8 @@
+/**
+ * @fileoverview Exports the processor.
+ * @author Brandon Mills
+ */
+
+"use strict";
+
+module.exports = require("./lib");

lib/configs/recommended.js

@@ -0,0 +1,53 @@
+"use strict";
+
+const markdown = require("../../index");
+
+module.exports = [
+    {
+        files: ["*.md"],
+        plugins: {
+            markdown
+        },
+        processor: "markdown/markdown"
+    },
+    {
+        files: ["**/*.md/**"],
+        plugins: {
+            markdown
+        },
+        languageOptions: {
+            parserOptions: {
+                ecmaFeatures: {
+
+                    // Adding a "use strict" directive at the top of
+                    // every code block is tedious and distracting, so
+                    // opt into strict mode parsing without the
+                    // directive.
+                    impliedStrict: true
+                }
+            }
+        },
+        rules: {
+
+            // The Markdown parser automatically trims trailing
+            // newlines from code blocks.
+            "eol-last": "off",
+
+            // In code snippets and examples, these rules are often
+            // counterproductive to clarity and brevity.
+            "no-undef": "off",
+            "no-unused-expressions": "off",
+            "no-unused-vars": "off",
+            "padded-blocks": "off",
+
+            // Adding a "use strict" directive at the top of every
+            // code block is tedious and distracting. The config
+            // opts into strict mode parsing without the directive.
+            strict: "off",
+
+            // The processor will not receive a Unicode Byte Order
+            // Mark from the Markdown parser.
+            "unicode-bom": "off"
+        }
+    }
+];

package.json

@@ -31,10 +31,20 @@
     "publish-release": "eslint-publish-release"
   },
   "main": "index.js",
+  "exports": {
+    ".": {
+      "import": "./index.js",
+      "require": "./legacy.js"
+    },
+    "./new": "./index.js",
+    "./recommended": "./lib/configs/recommended.js"
+  },
   "files": [
     "index.js",
+    "legacy.js",
     "lib/index.js",
-    "lib/processor.js"
+    "lib/processor.js",
+    "lib/configs/recommended.js"
   ],
   "devDependencies": {
     "chai": "^4.2.0",

tests/lib/plugin.js

@@ -9,7 +9,7 @@ const assert = require("chai").assert;
 const execSync = require("child_process").execSync;
 const { CLIEngine, ESLint } = require("eslint");
 const path = require("path");
-const plugin = require("../..");
+const plugin = require("../../legacy");
 
 /**
  * @typedef {import('eslint/lib/cli-engine/cli-engine').CLIEngineOptions} CLIEngineOptions