fix: missing register component in ssr (#1887)

Author: mog422

src/index.ts

@@ -363,6 +363,18 @@ export default function loader(
         .join(`\n`) + `\n`
   }
 
+  if (isServer) {
+    code += `\nimport { useSSRContext } from 'vue'\n`
+    code += `const _setup = script.setup\n`
+    ;(code += `script.setup = (props, ctx) => {`),
+      (code += `  const ssrContext = _useSSRContext()`),
+      (code += `  ;(ssrContext._registeredComponents || (ssrContext._registeredComponents = new Set())).add(${JSON.stringify(
+        hash(loaderContext.request)
+      )});`)
+    code += `  return _setup ? _setup(props, ctx) : undefined`
+    code += `}\n`
+  }
+
   // finalize
   if (!propsToAttach.length) {
     code += `\n\nconst __exports__ = script;`