fix(index): move the if check earlier to avoid creating unnecessary ssr when entering return block (#523)

Author: Aaron-zon

Diff for: packages/plugin-vue/src/index.ts

@@ -305,11 +305,12 @@ export default function vuePlugin(rawOptions: Options = {}): Plugin<Api> {
     },
 
     load(id, opt) {
-      const ssr = opt?.ssr === true
       if (id === EXPORT_HELPER_ID) {
         return helperCode
       }
 
+      const ssr = opt?.ssr === true
+
       const { filename, query } = parseVueRequest(id)
 
       // select corresponding block for sub-part virtual modules