fix(ssr): Transform named default exports without altering scope (#4053)

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>
vitejs · Jul 2, 2021 · 5211aaf · 5211aaf
1 parent a0a80f8
commit 5211aaf
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Showing 2 changed files with 67 additions and 6 deletions.
diff --git a/packages/vite/src/node/ssr/__tests__/ssrTransform.spec.ts b/packages/vite/src/node/ssr/__tests__/ssrTransform.spec.ts
@@ -211,8 +211,56 @@ test('should declare variable for imported super class', async () => {
   ).toMatchInlineSnapshot(`
     "const __vite_ssr_import_0__ = __vite_ssr_import__(\\"./dependency\\")
     const Foo = __vite_ssr_import_0__.Foo;
-    __vite_ssr_exports__.default = class A extends Foo {}
+    class A extends Foo {}
     class B extends Foo {}
+    Object.defineProperty(__vite_ssr_exports__, \\"default\\", { enumerable: true, value: A })
+    Object.defineProperty(__vite_ssr_exports__, \\"B\\", { enumerable: true, configurable: true, get(){ return B }})"
+  `)
+})
+
+// #4049
+test('should handle default export variants', async () => {
+  // default anonymous functions
+  expect(
+    (await ssrTransform(`export default function() {}\n`, null, null)).code
+  ).toMatchInlineSnapshot(`
+    "__vite_ssr_exports__.default = function() {}
+    "
+  `)
+  // default anonymous class
+  expect((await ssrTransform(`export default class {}\n`, null, null)).code)
+    .toMatchInlineSnapshot(`
+    "__vite_ssr_exports__.default = class {}
+    "
+  `)
+  // default named functions
+  expect(
+    (
+      await ssrTransform(
+        `export default function foo() {}\n` +
+          `foo.prototype = Object.prototype;`,
+        null,
+        null
+      )
+    ).code
+  ).toMatchInlineSnapshot(`
+    "function foo() {}
+    foo.prototype = Object.prototype;
+    Object.defineProperty(__vite_ssr_exports__, \\"default\\", { enumerable: true, value: foo })"
+  `)
+  // default named classes
+  expect(
+    (
+      await ssrTransform(
+        `export default class A {}\n` + `export class B extends A {}`,
+        null,
+        null
+      )
+    ).code
+  ).toMatchInlineSnapshot(`
+    "class A {}
+    class B extends A {}
+    Object.defineProperty(__vite_ssr_exports__, \\"default\\", { enumerable: true, value: A })
     Object.defineProperty(__vite_ssr_exports__, \\"B\\", { enumerable: true, configurable: true, get(){ return B }})"
   `)
 })

diff --git a/packages/vite/src/node/ssr/ssrTransform.ts b/packages/vite/src/node/ssr/ssrTransform.ts
@@ -124,11 +124,24 @@ export async function ssrTransform(
 
     // default export
     if (node.type === 'ExportDefaultDeclaration') {
-      s.overwrite(
-        node.start,
-        node.start + 14,
-        `${ssrModuleExportsKey}.default =`
-      )
+      if ('id' in node.declaration && node.declaration.id) {
+        // named hoistable/class exports
+        // export default function foo() {}
+        // export default class A {}
+        const { name } = node.declaration.id
+        s.remove(node.start, node.start + 15 /* 'export default '.length */)
+        s.append(
+          `\nObject.defineProperty(${ssrModuleExportsKey}, "default", ` +
+            `{ enumerable: true, value: ${name} })`
+        )
+      } else {
+        // anonymous default exports
+        s.overwrite(
+          node.start,
+          node.start + 14 /* 'export default'.length */,
+          `${ssrModuleExportsKey}.default =`
+        )
+      }
     }
 
     // export * from './foo'