diff --git a/README.md b/README.md
index 3383e0b..c8f65f2 100644
--- a/README.md
+++ b/README.md
@@ -24,11 +24,11 @@ Inside your `eslint.config.js`, pass the resolver to `eslint-plugin-import-x`:
 }
 ```
 
-This lib defaults to ESM, if you use CJS(not recommended), please wait for the subsequent release. Or you can configure it yourself according to the [documentation](https://github.com/oxc-project/oxc-resolver?tab=readme-ov-file#options).
-
 ### Options
 
-see [oxc-resolver](https://github.com/oxc-project/oxc-resolver?tab=readme-ov-file#options)
+Default options see [normalizeOptions.ts](./src/nomalizeOptions.ts)
+
+More info see [oxc-resolver](https://github.com/oxc-project/oxc-resolver?tab=readme-ov-file#options)
 
 ## Motivation
 
diff --git a/src/index.ts b/src/index.ts
index c05891c..257173e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,84 +1,6 @@
-import { cwd } from 'node:process'
 import type { NapiResolveOptions } from 'oxc-resolver'
 import { ResolverFactory } from 'oxc-resolver'
-
-// @keep-sorted
-/**
- * some default options copy from
- * https://github.com/import-js/eslint-import-resolver-typescript/blob/master/src/index.ts
- * https://github.com/rolldown/rolldown/blob/main/crates/rolldown_resolver/src/resolver.rs
- */
-const defaultOptions: NapiResolveOptions = {
-  aliasFields: [
-    ['browser'],
-  ],
-  conditionNames: [
-    'default',
-    'types',
-
-    'import',
-    'require',
-
-    'node',
-    'node-addons',
-    'browser',
-
-    // APF: https://angular.io/guide/angular-package-format
-    'esm2020',
-    'es2020',
-    'es2015',
-  ],
-  extensionAlias: {
-    '.js': [
-      '.ts',
-      // `.tsx` can also be compiled as `.js`
-      '.tsx',
-      '.d.ts',
-      '.js',
-    ],
-    '.jsx': ['.tsx', '.d.ts', '.jsx'],
-    '.cjs': ['.cts', '.d.cts', '.cjs'],
-    '.mjs': ['.mts', '.d.mts', '.mjs'],
-  },
-  extensions: [
-    '.ts',
-    '.tsx',
-    '.d.ts',
-    '.js',
-    '.jsx',
-    '.json',
-    '.node',
-  ],
-  mainFields: [
-    'types',
-    'typings',
-
-    // APF: https://angular.io/guide/angular-package-format
-    'fesm2020',
-    'fesm2015',
-    'esm2020',
-    'es2020',
-
-    'main',
-    'module',
-    'browser',
-    'jsnext:main',
-  ],
-  roots: [cwd()],
-}
-
-function normalizeOptions(options: NapiResolveOptions): NapiResolveOptions {
-  if (!options.tsconfig) {
-    defaultOptions.tsconfig = {
-      configFile: './tsconfig.json',
-      references: 'auto',
-    }
-  }
-  return {
-    ...defaultOptions,
-    ...options,
-  }
-}
+import { normalizeOptions } from './nomalizeOptions'
 
 let resolver: ResolverFactory | undefined
 export function resolve(source: string, file: string, options: NapiResolveOptions = {}): { found: boolean, path?: string } {
diff --git a/src/nomalizeOptions.ts b/src/nomalizeOptions.ts
new file mode 100644
index 0000000..76aee4c
--- /dev/null
+++ b/src/nomalizeOptions.ts
@@ -0,0 +1,80 @@
+import { cwd } from 'node:process'
+import type { NapiResolveOptions } from 'oxc-resolver'
+
+// @keep-sorted
+/**
+ * some default options copy from
+ * https://github.com/import-js/eslint-import-resolver-typescript/blob/master/src/index.ts
+ * https://github.com/rolldown/rolldown/blob/main/crates/rolldown_resolver/src/resolver.rs
+ */
+const defaultOptions: NapiResolveOptions = {
+  aliasFields: [
+    ['browser'],
+  ],
+  conditionNames: [
+    'default',
+    'types',
+
+    'import',
+    'require',
+
+    'node',
+    'node-addons',
+    'browser',
+
+    // APF: https://angular.io/guide/angular-package-format
+    'esm2020',
+    'es2020',
+    'es2015',
+  ],
+  extensionAlias: {
+    '.js': [
+      '.ts',
+      // `.tsx` can also be compiled as `.js`
+      '.tsx',
+      '.d.ts',
+      '.js',
+    ],
+    '.jsx': ['.tsx', '.d.ts', '.jsx'],
+    '.cjs': ['.cts', '.d.cts', '.cjs'],
+    '.mjs': ['.mts', '.d.mts', '.mjs'],
+  },
+  extensions: [
+    '.ts',
+    '.tsx',
+    '.d.ts',
+    '.js',
+    '.jsx',
+    '.json',
+    '.node',
+  ],
+  mainFields: [
+    'types',
+    'typings',
+
+    // APF: https://angular.io/guide/angular-package-format
+    'fesm2020',
+    'fesm2015',
+    'esm2020',
+    'es2020',
+
+    'main',
+    'module',
+    'browser',
+    'jsnext:main',
+  ],
+  roots: [cwd()],
+}
+
+export function normalizeOptions(options: NapiResolveOptions = {}): NapiResolveOptions {
+  if (!options.tsconfig) {
+    defaultOptions.tsconfig = {
+      configFile: './tsconfig.json',
+      references: 'auto',
+    }
+  }
+  return {
+    ...defaultOptions,
+    ...options,
+  }
+}