From c69f607db212150eca73e459be81e86ca7b0f70a Mon Sep 17 00:00:00 2001
From: Yusuke Wada <yusuke@kamawada.com>
Date: Sat, 13 Jan 2024 18:34:02 +0900
Subject: [PATCH] feat(vite): islands support async component

---
 src/vite/island-components.ts            | 27 ++++++++++++++++--------
 test/unit/vite/island-components.test.ts | 16 ++++++++++++++
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/src/vite/island-components.ts b/src/vite/island-components.ts
index 13bff55..90e6061 100644
--- a/src/vite/island-components.ts
+++ b/src/vite/island-components.ts
@@ -32,7 +32,7 @@ import {
 import type { Plugin } from 'vite'
 import { COMPONENT_NAME, DATA_SERIALIZED_PROPS } from '../constants.js'
 
-function addSSRCheck(funcName: string, componentName: string) {
+function addSSRCheck(funcName: string, componentName: string, isAsync = false) {
   const isSSR = memberExpression(
     memberExpression(identifier('import'), identifier('meta')),
     identifier('env.SSR')
@@ -70,7 +70,11 @@ function addSSRCheck(funcName: string, componentName: string) {
   )
 
   const returnStmt = returnStatement(conditionalExpression(isSSR, ssrElement, clientElement))
-  return functionExpression(null, [identifier('props')], blockStatement([returnStmt]))
+  const functionExpr = functionExpression(null, [identifier('props')], blockStatement([returnStmt]))
+  if (isAsync) {
+    functionExpr.async = true
+  }
+  return functionExpr
 }
 
 export const transformJsxTags = (contents: string, componentName: string) => {
@@ -85,18 +89,23 @@ export const transformJsxTags = (contents: string, componentName: string) => {
         if (path.node.declaration.type === 'FunctionDeclaration') {
           const functionId = path.node.declaration.id
           if (!functionId) return
+          const isAsync = path.node.declaration.async
           const originalFunctionId = identifier(functionId.name + 'Original')
 
+          const originalFunction = functionExpression(
+            null,
+            path.node.declaration.params,
+            path.node.declaration.body
+          )
+          if (isAsync) {
+            originalFunction.async = true
+          }
+
           path.insertBefore(
-            variableDeclaration('const', [
-              variableDeclarator(
-                originalFunctionId,
-                functionExpression(null, path.node.declaration.params, path.node.declaration.body)
-              ),
-            ])
+            variableDeclaration('const', [variableDeclarator(originalFunctionId, originalFunction)])
           )
 
-          const wrappedFunction = addSSRCheck(originalFunctionId.name, componentName)
+          const wrappedFunction = addSSRCheck(originalFunctionId.name, componentName, isAsync)
           const wrappedFunctionId = identifier('Wrapped' + functionId.name)
           path.replaceWith(
             variableDeclaration('const', [variableDeclarator(wrappedFunctionId, wrappedFunction)])
diff --git a/test/unit/vite/island-components.test.ts b/test/unit/vite/island-components.test.ts
index f5b8840..ddb8ef3 100644
--- a/test/unit/vite/island-components.test.ts
+++ b/test/unit/vite/island-components.test.ts
@@ -20,4 +20,20 @@ export default WrappedBadge;`
     const code = transformJsxTags('', 'Badge.tsx')
     expect(code).toBe('')
   })
+
+  it('async', () => {
+    const code = `export default async function AsyncComponent() {
+      return <h1>Hello</h1>
+    }`
+    const result = transformJsxTags(code, 'AsyncComponent.tsx')
+    expect(result).toBe(
+      `const AsyncComponentOriginal = async function () {
+  return <h1>Hello</h1>;
+};
+const WrappedAsyncComponent = async function (props) {
+  return import.meta.env.SSR ? <honox-island component-name="AsyncComponent.tsx" data-serialized-props={JSON.stringify(props)}><AsyncComponentOriginal {...props}></AsyncComponentOriginal></honox-island> : <AsyncComponentOriginal {...props}></AsyncComponentOriginal>;
+};
+export default WrappedAsyncComponent;`
+    )
+  })
 })