Pull magicString from transform meta instead of constructing new instances

Reuse the lazily-created RolldownMagicString that Rolldown provides
via the transform hook's meta parameter, avoiding redundant instance
creation. The wrapLayout and wrapIslandsInSFC helpers now receive the
magic string from their callers instead of constructing their own.

https://claude.ai/code/session_01Gk9SG3CqsszLBotJRTf45S

Author: claude

packages/iles/src/node/plugin/plugin.ts

@@ -3,7 +3,7 @@ import { basename, resolve, relative } from 'pathe'
 import type { PluginOption, ResolvedConfig, ViteDevServer } from 'vite'
 import { transformWithOxc } from 'vite'
 
-import { RolldownMagicString as MagicString } from 'rolldown'
+import type { RolldownMagicString as MagicString } from 'rolldown'
 
 import type { AppConfig, AppClientConfig } from '../shared'
 import { ILES_APP_ENTRY } from '../constants'
@@ -128,25 +128,25 @@ export default function IslandsPlugins (appConfig: AppConfig): PluginOption[] {
     {
       name: 'iles:detect-islands-in-vue',
       enforce: 'pre',
-      async transform (code, id) {
+      async transform (code, id, meta) {
         const { path, query } = parseId(id)
 
         if (query.vue !== undefined && query.type === 'script-client')
           return 'export default {}; if (import.meta.hot) import.meta.hot.accept()'
 
         if (isSFCMain(path, query) && code.includes('client:') && code.includes('<template'))
-          return wrapIslandsInSFC(appConfig, code, path)
+          return wrapIslandsInSFC(appConfig, code, path, (meta as any).magicString)
       },
     },
     {
       name: 'iles:layouts',
       enforce: 'pre',
-      transform (code, id) {
+      transform (code, id, meta) {
         const { path, query } = parseId(id)
         if (!isSFCMain(path, query) || !isLayout(path)) return
         const layoutName = code.match(templateLayoutRegex)?.[1] || false
         if (String(layoutName) === 'false') return
-        return wrapLayout(code, path)
+        return wrapLayout(code, path, (meta as any).magicString)
       },
     },
 
@@ -171,7 +171,7 @@ export default function IslandsPlugins (appConfig: AppConfig): PluginOption[] {
     {
       name: 'iles:page-data',
       enforce: 'post',
-      async transform (code, id, options) {
+      async transform (code, id, transformMeta) {
         const { path, query } = parseId(id)
         const isMdx = isMarkdown(path)
         if (!isMdx && !isVueScript(path, query)) return
@@ -184,7 +184,7 @@ export default function IslandsPlugins (appConfig: AppConfig): PluginOption[] {
         if (!sfcIndex || sfcIndex === -1)
           return
 
-        const s = new MagicString(code)
+        const s = (transformMeta as any).magicString as MagicString
         const appendToSfc = (key: string, value?: string) =>
           s.appendRight(sfcIndex, value ? `${key}:${value},` : `${key},`)
 

packages/iles/src/node/plugin/wrap.ts

@@ -1,4 +1,4 @@
-import { RolldownMagicString as MagicString } from 'rolldown'
+import type { RolldownMagicString as MagicString } from 'rolldown'
 import type { SFCBlock } from 'vue/compiler-sfc'
 import { parse } from 'vue/compiler-sfc'
 import type { ComponentInfo, PublicPluginAPI as ComponentsApi } from 'unplugin-vue-components/types'
@@ -15,12 +15,10 @@ interface SfcRootNode extends RootNode {
 
 export const unresolvedIslandKey = '__viteIslandComponent'
 
-export async function wrapLayout (code: string, filename: string) {
+export async function wrapLayout (code: string, filename: string, s: MagicString) {
   const { descriptor: { template }, errors } = parse(code, { filename })
   if (errors.length > 0 || !template || !isString(template.attrs.layout)) return
 
-  const s = new MagicString(code)
-
   const nodes = template.ast?.children
   if (!nodes?.length) {
     return
@@ -38,9 +36,14 @@ export async function wrapLayout (code: string, filename: string) {
 
 const scriptClientRE = /<script\b([^>]*\bclient:[^>]*)>([^]*?)<\/script>/
 
-export async function wrapIslandsInSFC (config: AppConfig, code: string, filename: string) {
-  code = code.replace(scriptClientRE, (_, attrs, content) =>
-    `<script-client${attrs}>${content}</script-client>`)
+export async function wrapIslandsInSFC (config: AppConfig, code: string, filename: string, s: MagicString) {
+  const match = scriptClientRE.exec(code)
+  if (match) {
+    const [full, attrs, content] = match
+    const replacement = `<script-client${attrs}>${content}</script-client>`
+    s.overwrite(match.index, match.index + full.length, replacement)
+    code = s.toString()
+  }
 
   const { descriptor: { template, script, scriptSetup, customBlocks }, errors } = parse(code, { filename })
   const scriptClientIndex = customBlocks.findIndex(b => b.type === 'script-client')
@@ -55,8 +58,6 @@ export async function wrapIslandsInSFC (config: AppConfig, code: string, filenam
     return
   }
   const sfcRootNode = template.ast as any as SfcRootNode
-
-  const s = new MagicString(code)
   const components: ComponentsApi = config.namedPlugins.components.api
 
   if (scriptClient) { await injectClientScript(sfcRootNode, s, filename, scriptClientIndex, scriptClient) }