chore(eslint): standardise on flat base + plugin-recommended spread (#35)

Author: mridang

eslint.config.mjs

@@ -1,27 +1,28 @@
 import js from '@eslint/js';
-import globals from 'globals';
-import tseslint from 'typescript-eslint';
-import { globalIgnores } from 'eslint/config';
+import ts from 'typescript-eslint';
 import { qwikEslint9Plugin } from 'eslint-plugin-qwik';
 import prettier from 'eslint-config-prettier';
+import globals from 'globals';
 
-const ignores = ['dist/**', 'node_modules/**', 'build/**', 'server/**'];
-
-export default tseslint.config(
-  globalIgnores(ignores),
+export default ts.config(
+  {
+    ignores: [
+      'node_modules/**',
+      'dist/**',
+      'build/**',
+      'coverage/**',
+      'server/**',
+    ],
+  },
   js.configs.recommended,
-  tseslint.configs.recommended,
-  qwikEslint9Plugin.configs.recommended,
-  prettier,
+  ...ts.configs.recommended,
   {
+    files: ['**/*.{ts,tsx}'],
     languageOptions: {
-      globals: {
-        ...globals.browser,
-        ...globals.node,
-        ...globals.es2021,
-        ...globals.serviceworker,
-      },
+      parser: ts.parser,
       parserOptions: {
+        ecmaVersion: 'latest',
+        sourceType: 'module',
         projectService: {
           allowDefaultProject: [
             'knip.config.js',
@@ -33,11 +34,36 @@ export default tseslint.config(
         },
         tsconfigRootDir: import.meta.dirname,
       },
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+        ...globals.es2021,
+        ...globals.serviceworker,
+      },
+    },
+  },
+  {
+    files: ['**/*.{js,mjs}'],
+    languageOptions: {
+      globals: { ...globals.node, ...globals.es2021 },
     },
   },
   {
+    files: ['**/*.{test,spec}.{ts,tsx,js,mjs}', 'test/**/*.{ts,tsx,js,mjs}'],
+    languageOptions: { globals: { ...globals.jest, ...globals.node } },
+  },
+  // qwik plugin rules need TS type info — restrict to TS files so they
+  // don't try to type-check the config file itself.
+  ...qwikEslint9Plugin.configs.recommended.map((c) => ({
+    ...c,
+    files: ['**/*.{ts,tsx}'],
+  })),
+  {
+    files: ['**/*.{ts,tsx}'],
     rules: {
+      // Pre-existing override: qwik examples use `any` deliberately.
       '@typescript-eslint/no-explicit-any': 'off',
     },
   },
+  prettier,
 );