fix: support ts-module (#23)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Enhanced compatibility with TypeScript modules for improved import
functionality.
  
- **Tests**
- Added comprehensive test cases to validate TypeScript module imports,
covering default imports, named exports, and module-level exports,
ensuring robust and reliable behavior.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

src/import.ts

@@ -55,7 +55,7 @@ export async function importModule(filepath: string, options?: ImportModuleOptio
     //   one: 1,
     //   [Symbol(Symbol.toStringTag)]: 'Module'
     // }
-    if (obj?.__esModule === true && obj?.default?.__esModule === true) {
+    if (obj?.default?.__esModule === true && 'default' in obj?.default) {
       // 兼容 cjs 模拟 esm 的导出格式
       // {
       //   __esModule: true,
@@ -69,6 +69,18 @@ export async function importModule(filepath: string, options?: ImportModuleOptio
       //   },
       //   [Symbol(Symbol.toStringTag)]: 'Module'
       // }
+      // 兼容 ts module
+      // {
+      //   default: {
+      //     [__esModule]: true,
+      //     default: <ref *1> [Function: default_1] {
+      //       [length]: 0,
+      //       [name]: 'default_1',
+      //       [prototype]: { [constructor]: [Circular *1] }
+      //     }
+      //   },
+      //   [Symbol(Symbol.toStringTag)]: 'Module'
+      // }
       obj = obj.default;
     }
     if (options?.importDefaultOnly) {

test/fixtures/ts-module/exports.ts

@@ -0,0 +1,2 @@
+export const foo = 'bar';
+export const one = 1;

test/fixtures/ts-module/index.ts

@@ -0,0 +1,5 @@
+export default {
+  foo: 'bar',
+};
+
+export const one = 1;

test/fixtures/ts-module/mod.ts

@@ -0,0 +1,3 @@
+export default function() {
+  return { a: 1 };
+}

test/import.test.ts

@@ -84,6 +84,40 @@ describe('test/import.test.ts', () => {
       assert.equal(obj.one, 1);
     });
 
+    it('should work on ts-module', async () => {
+      let obj = await importModule(getFilepath('ts-module'));
+      assert.deepEqual(Object.keys(obj), [ 'default', 'one' ]);
+      assert.equal(obj.one, 1);
+      assert.deepEqual(obj.default, { foo: 'bar' });
+
+      obj = await importModule(getFilepath('ts-module'), { importDefaultOnly: true });
+      assert.deepEqual(obj, { foo: 'bar' });
+
+      obj = await importModule(getFilepath('ts-module/exports'));
+      assert.deepEqual(Object.keys(obj), [ 'foo', 'one' ]);
+      assert.equal(obj.foo, 'bar');
+      assert.equal(obj.one, 1);
+
+      obj = await importModule(getFilepath('ts-module/exports'), { importDefaultOnly: true });
+      assert.deepEqual(Object.keys(obj), [ 'foo', 'one' ]);
+      assert.equal(obj.foo, 'bar');
+      assert.equal(obj.one, 1);
+
+      obj = await importModule(getFilepath('ts-module/exports.ts'));
+      assert.deepEqual(Object.keys(obj), [ 'foo', 'one' ]);
+      assert.equal(obj.foo, 'bar');
+      assert.equal(obj.one, 1);
+
+      obj = await importModule(getFilepath('ts-module/mod'));
+      assert.deepEqual(Object.keys(obj), [ 'default' ]);
+      assert.equal(typeof obj.default, 'function');
+
+      obj = await importModule(getFilepath('ts-module/mod.ts'), {
+        importDefaultOnly: true,
+      });
+      assert.equal(typeof obj, 'function');
+    });
+
     it('should support module.exports = null', async () => {
       assert.equal(await importModule(getFilepath('cjs/module-exports-null.js'), {
         importDefaultOnly: true,