fix(#185): add langaugeOptions.parserOptions to flat preset / read sourceType w/ fallback

.changeset/neat-houses-deliver.md

@@ -0,0 +1,28 @@
+---
+"eslint-plugin-import-x": patch
+---
+
+Add a default `languageOptions.parserOptions` to the `recommended` flat config presets. This prevents the `sourceType 'module' is not supported when ecmaVersion < 2015` error when no custom parser options are provided.
+
+For existing users who are already using the `recommended` flat config presets while providing custom parser options, make sure your custom parser options come after the presets to prevent yours from being overridden:
+
+```js
+// eslint.config.js
+import eslintPluginImportX from 'eslint-plugin-import-x'
+
+export default [
+  js.configs.recommended,
+  eslintPluginImportX.flatConfigs.recommended,
+  // Always put your custom language options and parser options after the presets
+  {
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+      parserOptions: {
+        ecmaVersion: 'latest',
+        sourceType: 'module',
+      },
+    },
+  },
+]
+```

.changeset/violet-ligers-fail.md

@@ -0,0 +1,5 @@
+---
+"eslint-plugin-import-x": patch
+---
+
+Change how the `sourceType` is read from the ESLint rule context.

.eslintrc.js

@@ -41,6 +41,7 @@ module.exports = {
     'n/no-missing-import': 'off',
     'n/no-missing-require': 'off',
     'n/no-unsupported-features/es-syntax': 'off',
+    'unicorn/expiring-todo-comments': 'off',
     'unicorn/no-array-callback-reference': 'off',
     'unicorn/no-array-reduce': 'off',
     'unicorn/no-null': 'off',

src/config/flat/recommended.ts

@@ -23,5 +23,9 @@ export default {
   languageOptions: {
     ecmaVersion: 2018,
     sourceType: 'module',
+    parserOptions: {
+      ecmaVersion: 2018,
+      sourceType: 'module',
+    },
   },
 } satisfies PluginFlatBaseConfig

src/utils/source-type.ts

@@ -1,10 +1,19 @@
 import type { RuleContext } from '../types'
 
 export default function sourceType(context: RuleContext) {
-  if ('sourceType' in context.parserOptions) {
-    return context.parserOptions.sourceType
-  }
   if ('languageOptions' in context && context.languageOptions) {
-    return context.languageOptions.sourceType
+    if (
+      'parserOptions' in context.languageOptions &&
+      context.languageOptions.parserOptions &&
+      context.languageOptions.parserOptions.sourceType
+    ) {
+      return context.languageOptions.parserOptions.sourceType
+    }
+    if (context.languageOptions.sourceType) {
+      return context.languageOptions.sourceType
+    }
+  }
+  if (context.parserOptions.sourceType) {
+    return context.parserOptions.sourceType
   }
 }