From ab6504514d23e74dd5ef0c653238fb36c48e689a Mon Sep 17 00:00:00 2001
From: Haoqun Jiang <haoqunjiang@gmail.com>
Date: Mon, 1 Nov 2021 16:43:03 +0800
Subject: [PATCH] test: add a test case for issue #3040

---
 packages/playground/resolve/__tests__/resolve.spec.ts | 4 ++++
 packages/playground/resolve/index.html                | 8 ++++++++
 packages/playground/resolve/ts-extension/hello.ts     | 1 +
 packages/playground/resolve/ts-extension/index.ts     | 3 +++
 packages/playground/resolve/vite.config.js            | 2 +-
 5 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 packages/playground/resolve/ts-extension/hello.ts
 create mode 100644 packages/playground/resolve/ts-extension/index.ts

diff --git a/packages/playground/resolve/__tests__/resolve.spec.ts b/packages/playground/resolve/__tests__/resolve.spec.ts
index b94be689371b22..b1524e1e42aa08 100644
--- a/packages/playground/resolve/__tests__/resolve.spec.ts
+++ b/packages/playground/resolve/__tests__/resolve.spec.ts
@@ -54,6 +54,10 @@ test('dont add extension to directory name (./dir-with-ext.js/index.js)', async
   expect(await page.textContent('.dir-with-ext')).toMatch('[success]')
 })
 
+test('a ts module can import another ts module using its corresponding js file name', async () => {
+  expect(await page.textContent('.ts-extension')).toMatch('[success]')
+})
+
 test('filename with dot', async () => {
   expect(await page.textContent('.dot')).toMatch('[success]')
 })
diff --git a/packages/playground/resolve/index.html b/packages/playground/resolve/index.html
index a121c5c8a68ca1..9dc6525fcd7a43 100644
--- a/packages/playground/resolve/index.html
+++ b/packages/playground/resolve/index.html
@@ -33,6 +33,11 @@ <h2>Resolve to non-duplicated file extension</h2>
 <h2>Don't add extensions to directory names</h2>
 <p class="dir-with-ext">fail</p>
 
+<h2>
+  A ts module can import another ts module using its corresponding js file name
+</h2>
+<p class="ts-extension">fail</p>
+
 <h2>Resolve file name containing dot</h2>
 <p class="dot">fail</p>
 
@@ -119,6 +124,9 @@ <h2>resolve package that contains # in path</h2>
   import { file as dirWithExtMsg } from './dir-with-ext'
   text('.dir-with-ext', dirWithExtMsg)
 
+  import { msg as tsExtensionMsg } from './ts-extension'
+  text('.ts-extension', tsExtensionMsg)
+
   // filename with dot
   import { bar } from './util/bar.util'
   text('.dot', bar())
diff --git a/packages/playground/resolve/ts-extension/hello.ts b/packages/playground/resolve/ts-extension/hello.ts
new file mode 100644
index 00000000000000..0189355c3fe06f
--- /dev/null
+++ b/packages/playground/resolve/ts-extension/hello.ts
@@ -0,0 +1 @@
+export const msg = '[success] use .js extension to import a ts module'
diff --git a/packages/playground/resolve/ts-extension/index.ts b/packages/playground/resolve/ts-extension/index.ts
new file mode 100644
index 00000000000000..e095619ee4d716
--- /dev/null
+++ b/packages/playground/resolve/ts-extension/index.ts
@@ -0,0 +1,3 @@
+import { msg } from './hello.js'
+
+export { msg }
diff --git a/packages/playground/resolve/vite.config.js b/packages/playground/resolve/vite.config.js
index a05d51bb5b8e45..e7d531097add7c 100644
--- a/packages/playground/resolve/vite.config.js
+++ b/packages/playground/resolve/vite.config.js
@@ -2,7 +2,7 @@ const virtualFile = '@virtual-file'
 
 module.exports = {
   resolve: {
-    extensions: ['.mjs', '.js', '.es'],
+    extensions: ['.mjs', '.js', '.es', '.ts'],
     mainFields: ['custom', 'module'],
     conditions: ['custom']
   },