Part 9b: refactor: migrate to Node16 module resolution and ESLint flat config

src/content/9/en/part9b.md

@@ -622,7 +622,8 @@ Let's specify the following configuration in our *tsconfig.json* file:
     "noFallthroughCasesInSwitch": true,
     "noImplicitAny": true, // highlight-line
     "esModuleInterop": true,
-    "moduleResolution": "node"
+    "module": "node16",
+    "moduleResolution": "node16"
   }
 }
 ```
@@ -733,7 +734,8 @@ This is because we banned unused parameters in our *tsconfig.json*:
     "noFallthroughCasesInSwitch": true,
     "noImplicitAny": true,
     "esModuleInterop": true,
-    "moduleResolution": "node"
+    "module": "node16",
+    "moduleResolution": "node16"
   }
 }
 ```
@@ -907,22 +909,32 @@ We will configure ESlint to [disallow explicit any](https://github.com/typescrip
 import eslint from '@eslint/js';
 import tseslint from 'typescript-eslint';
 
-export default tseslint.config({
-  files: ['**/*.ts'],
-  extends: [
-    eslint.configs.recommended,
-    ...tseslint.configs.recommendedTypeChecked,
-  ],
-  languageOptions: {
-    parserOptions: {
-      project: true,
-      tsconfigRootDir: import.meta.dirname,
-    },
+export default [
+  {
+    ignores: ["dist/**", "build/**", "eslint.config.*", "**/*.js", "**/*.mjs"],
   },
-  rules: {
-    '@typescript-eslint/no-explicit-any': 'error',
+  {
+    files: ["**/*.ts"],
   },
-});
+
+  // Base ESLint recommended rules
+  eslint.configs.recommended,
+
+  // TypeScript ESLint rules (type-aware)
+  ...tseslint.configs.recommendedTypeChecked,
+
+  {
+    languageOptions: {
+      parserOptions: {
+        project: true, // looks for tsconfig.json automatically
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+    rules: {
+      "@typescript-eslint/no-explicit-any": "error",
+    },
+  },
+];
 ```
 
 Let us also set up a *lint* npm script to inspect the files by modifying the *package.json* file:
@@ -955,39 +967,49 @@ npm install --save-dev @stylistic/eslint-plugin
 Our final *eslint.config.mjs* looks as follows:
 
 ```js
-import eslint from '@eslint/js';
-import tseslint from 'typescript-eslint';
+import eslint from "@eslint/js";
+import tseslint from "typescript-eslint";
 import stylistic from "@stylistic/eslint-plugin";
 
-export default tseslint.config({
-  files: ['**/*.ts'],
-  extends: [
-    eslint.configs.recommended,
-    ...tseslint.configs.recommendedTypeChecked,
-  ],
-  languageOptions: {
-    parserOptions: {
-      project: true,
-      tsconfigRootDir: import.meta.dirname,
-    },
+export default [
+  {
+    ignores: ["dist/**", "build/**", "eslint.config.*", "**/*.js", "**/*.mjs"],
   },
-  plugins: {
-    "@stylistic": stylistic,
+  {
+    files: ["**/*.ts"],
   },
-  rules: {
-    '@stylistic/semi': 'error',
-    '@typescript-eslint/no-unsafe-assignment': 'error',
-    '@typescript-eslint/no-explicit-any': 'error',
-    '@typescript-eslint/explicit-function-return-type': 'off',
-    '@typescript-eslint/explicit-module-boundary-types': 'off',
-    '@typescript-eslint/restrict-template-expressions': 'off',
-    '@typescript-eslint/restrict-plus-operands': 'off',
-    '@typescript-eslint/no-unused-vars': [
-      'error',
-      { 'argsIgnorePattern': '^_' }
-    ],
+
+  // Base ESLint recommended rules
+  eslint.configs.recommended,
+
+  // TypeScript ESLint rules (type-aware)
+  ...tseslint.configs.recommendedTypeChecked,
+
+  {
+    languageOptions: {
+      parserOptions: {
+        project: true, // looks for tsconfig.json automatically
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+    plugins: {
+      "@stylistic": stylistic,
+    },
+    rules: {
+      "@stylistic/semi": "error",
+      "@typescript-eslint/no-unsafe-assignment": "error",
+      "@typescript-eslint/no-explicit-any": "error",
+      "@typescript-eslint/explicit-function-return-type": "off",
+      "@typescript-eslint/explicit-module-boundary-types": "off",
+      "@typescript-eslint/restrict-template-expressions": "off",
+      "@typescript-eslint/restrict-plus-operands": "off",
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_" },
+      ],
+    },
   },
-});
+];
 ```
 
 Quite a few semicolons are missing, but those are easy to add. We also have to solve the ESlint issues concerning the *any* type: