Interpolate default exports

examples/esm/.gitignore

@@ -0,0 +1,34 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# local env files
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# vercel
+.vercel

examples/esm/package.json

@@ -0,0 +1,14 @@
+{
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "next",
+    "build": "next build",
+    "start": "next start"
+  },
+  "dependencies": {
+    "next": "latest",
+    "react": "^18.0.0",
+    "react-dom": "^18.0.0"
+  }
+}

examples/esm/pages/index.js

@@ -0,0 +1,3 @@
+export default function Page() {
+  return <p>hello world</p>
+}

examples/esm/pages/modules.js

@@ -0,0 +1,13 @@
+import Link from 'next/link'
+import Image from 'next/image'
+
+export default function Modules() {
+  return (
+    <>
+      <Link href="/">
+        <a id="link-to-home">link to home</a>
+      </Link>
+      <Image src="/static/image.png" width="100" height="100" />
+    </>
+  )
+}

packages/next/taskfile-swc.js

@@ -14,7 +14,11 @@ module.exports = function (task) {
     function* (
       file,
       serverOrClient,
-      { stripExtension, keepImportAssertions = false } = {}
+      {
+        stripExtension,
+        keepImportAssertions = false,
+        interopClientDefaultExport = false,
+      } = {}
     ) {
       // Don't compile .d.ts
       if (file.base.endsWith('.d.ts')) return
@@ -113,6 +117,15 @@ module.exports = function (task) {
       if (output.map) {
         const map = `${file.base}.map`
 
+        if (interopClientDefaultExport) {
+          output.code += `
+if (typeof exports.default === 'function' || (typeof exports.default === 'object' && exports.default !== null)) {
+  Object.assign(exports.default, exports);
+  module.exports = exports.default;
+}
+`
+        }
+
         output.code += Buffer.from(`\n//# sourceMappingURL=${map}`)
 
         // add sourcemap to `files` array

packages/next/taskfile.js

@@ -1826,7 +1826,7 @@ export async function nextbuild(task, opts) {
 export async function client(task, opts) {
   await task
     .source(opts.src || 'client/**/*.+(js|ts|tsx)')
-    .swc('client', { dev: opts.dev })
+    .swc('client', { dev: opts.dev, interopClientDefaultExport: true })
     .target('dist/client')
   notify('Compiled client files')
 }

test/e2e/type-module-interop/index.test.ts

@@ -19,10 +19,16 @@ describe('Type module interop', () => {
           import Link from 'next/link'
           import Image from 'next/image'
 
-          return <>
-            <Link href="/"><a id="link-to-home">link to home</a></Link>
-            <Image src="/static/image.png" width="100" height="100" />
-          </>
+          export default function Modules() {
+            return (
+              <>
+                <Link href="/">
+                  <a id="link-to-home">link to home</a>
+                </Link>
+                <Image src="/static/image.png" width="100" height="100" />
+              </>
+            )
+          }
         `,
       },
       dependencies: {},