fix: add type tests (#305)

.github/workflows/ci.yml

@@ -71,6 +71,21 @@ jobs:
               run: npm install eslint@${{  matrix.eslint  }}
             - name: Test
               run: npm run test
+    test_types:
+        name: Test Types
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - name: Setup Node.js
+              uses: actions/setup-node@v4
+              with:
+                  node-version: "lts/*"
+            - name: Install dependencies
+              run: npm install
+            - name: Build
+              run: npm run build
+            - name: Check Types
+              run: npm run test:types
     jsr_test:
         name: Verify JSR Publish
         runs-on: ubuntu-latest

package.json

@@ -57,7 +57,8 @@
     "build:readme": "node tools/update-readme.js",
     "prepare": "node ./npm-prepare.cjs && npm run build",
     "test": "c8 mocha \"tests/**/*.test.js\" --timeout 30000",
-    "test:jsr": "npx jsr@latest publish --dry-run"
+    "test:jsr": "npx jsr@latest publish --dry-run",
+    "test:types": "tsc -p tests/types/tsconfig.json"
   },
   "devDependencies": {
     "@eslint/core": "^0.6.0",

src/index.js

@@ -49,7 +49,8 @@ const processorRulesConfig = {
 	"unicode-bom": "off",
 };
 
-/** @type {Plugin & { languages: Record<string,Language>}} */
+let recommendedPlugins, processorPlugins;
+
 const plugin = {
 	meta: {
 		name: "@eslint/markdown",
@@ -88,52 +89,48 @@ const plugin = {
 				},
 			],
 		},
-	},
-};
-
-plugin.configs.recommended = [
-	/** @type {Config & {language:string}} */
-	({
-		name: "markdown/recommended",
-		files: ["**/*.md"],
-		language: "markdown/commonmark",
-		plugins: {
-			markdown: plugin,
-		},
-		rules: /** @type {RulesRecord} */ (recommendedRules),
-	}),
-];
-
-plugin.configs.processor = [
-	{
-		name: "markdown/recommended/plugin",
-		plugins: {
-			markdown: plugin,
-		},
-	},
-	{
-		name: "markdown/recommended/processor",
-		files: ["**/*.md"],
-		processor: "markdown/markdown",
-	},
-	{
-		name: "markdown/recommended/code-blocks",
-		files: ["**/*.md/**"],
-		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,
+		recommended: [
+			{
+				name: "markdown/recommended",
+				files: ["**/*.md"],
+				language: "markdown/commonmark",
+				plugins: (recommendedPlugins = {}),
+				rules: recommendedRules,
+			},
+		],
+		processor: [
+			{
+				name: "markdown/recommended/plugin",
+				plugins: (processorPlugins = {}),
+			},
+			{
+				name: "markdown/recommended/processor",
+				files: ["**/*.md"],
+				processor: "markdown/markdown",
+			},
+			{
+				name: "markdown/recommended/code-blocks",
+				files: ["**/*.md/**"],
+				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: {
+					...processorRulesConfig,
 				},
 			},
-		},
-		rules: {
-			...processorRulesConfig,
-		},
+		],
 	},
-];
+};
+
+// @ts-expect-error
+recommendedPlugins.markdown = processorPlugins.markdown = plugin;
 
 export default plugin;

tests/types/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "emitDeclarationOnly": false,
+    "noEmit": true,
+    "rootDir": "../..",
+    "strict": true
+  },
+  "files": ["../../dist/esm/index.d.ts", "types.test.ts"]
+}

tests/types/types.test.ts

@@ -0,0 +1,37 @@
+import markdown from "@eslint/markdown";
+import { ESLint, Linter } from "eslint";
+
+markdown satisfies ESLint.Plugin;
+markdown.meta.name satisfies string;
+markdown.meta.version satisfies string;
+
+// Check that the processor is defined:
+markdown.processors.markdown satisfies object;
+
+// Check that these languages are defined:
+markdown.languages.commonmark satisfies object;
+markdown.languages.gfm satisfies object;
+
+markdown.configs["recommended-legacy"] satisfies Linter.LegacyConfig;
+markdown.configs.recommended satisfies Linter.Config[];
+markdown.configs.processor satisfies Linter.Config[];
+
+// Check that `plugins` in the recommended config is empty:
+const [{ plugins: recommendedPlugins }] = markdown.configs.recommended;
+typeof recommendedPlugins satisfies {};
+({}) satisfies typeof recommendedPlugins;
+
+// Check that `plugins` in the processor config is empty:
+const [{ plugins: processorPlugins }] = markdown.configs.processor;
+typeof processorPlugins satisfies {};
+({}) satisfies typeof processorPlugins;
+
+{
+	type RecommendedRuleName =
+		keyof (typeof markdown.configs.recommended)[0]["rules"];
+	type RuleName = `markdown/${keyof typeof markdown.rules}`;
+	type AssertAllNamesIn<T1 extends T2, T2> = never;
+
+	// Check that all recommended rule names match the names of existing rules in this plugin.
+	null as AssertAllNamesIn<RecommendedRuleName, RuleName>;
+}

tools/build-rules.js

@@ -33,9 +33,11 @@ for (const ruleId of rules) {
 	}
 }
 
-const output = `export default {
+const output = `const rules = /** @type {const} */ ({
     ${recommended.map(id => `"markdown/${id.slice(0, -3)}": "error"`).join(",\n    ")}
-};
+});
+
+export default rules;
 `;
 
 fs.mkdirSync(path.resolve(thisDir, "../src/build"), { recursive: true });