diff --git a/build.config.ts b/build.config.ts
index 3256888..db91d08 100644
--- a/build.config.ts
+++ b/build.config.ts
@@ -1,5 +1,6 @@
 import fs from 'node:fs/promises'
 import { defineBuildConfig } from 'unbuild'
+import colors from 'picocolors'
 
 export default defineBuildConfig({
   entries: ['src/index'],
@@ -20,21 +21,81 @@ export default defineBuildConfig({
   },
   hooks: {
     async 'build:done'(ctx) {
-      // Remove duplicated `dist/chunks/certificate.{cjs,mjs}` chunks
-      // as both are only dynamically imported by the entrypoints. The
-      // dynamic import can use the `.mjs` chunk only instead.
-      await fs.rm('dist/chunks/certificate.cjs')
-      const indexCjs = await fs.readFile('dist/index.cjs', 'utf8')
-      const editedIndexCjs = indexCjs.replace(
-        'chunks/certificate.cjs',
-        'chunks/certificate.mjs',
-      )
-      if (indexCjs === editedIndexCjs) {
-        throw new Error(
-          'Failed to find `dist/chunks/certificate.cjs` in `dist/index.cjs`',
-        )
+      const isBuild = ctx.options.stub === false
+      if (isBuild) {
+        await dedupeCertificateChunk()
+        await patchCJS()
       }
-      await fs.writeFile('dist/index.cjs', editedIndexCjs)
     },
   },
 })
+
+// Remove duplicated `dist/chunks/certificate.{cjs,mjs}` chunks
+// as both are only dynamically imported by the entrypoints. The
+// dynamic import can use the `.mjs` chunk only instead.
+async function dedupeCertificateChunk() {
+  await fs.rm('dist/chunks/certificate.cjs')
+  const indexCjs = await fs.readFile('dist/index.cjs', 'utf8')
+  const editedIndexCjs = indexCjs.replace(
+    'chunks/certificate.cjs',
+    'chunks/certificate.mjs',
+  )
+  if (indexCjs === editedIndexCjs) {
+    throw new Error(
+      'Failed to find `dist/chunks/certificate.cjs` in `dist/index.cjs`',
+    )
+  }
+  await fs.writeFile('dist/index.cjs', editedIndexCjs)
+}
+
+/**
+
+It converts
+
+```ts
+exports["default"] = viteBasicSslPlugin;
+```
+
+to
+
+```ts
+module.exports = viteBasicSslPlugin;
+module.exports["default"] = viteBasicSslPlugin;
+```
+*/
+async function patchCJS() {
+  const indexPath = 'dist/index.cjs'
+  let code = await fs.readFile(indexPath, 'utf-8')
+
+  const matchMixed = code.match(/\nexports\["default"\] = (\w+);/)
+  if (matchMixed) {
+    const name = matchMixed[1]
+
+    const lines = code.trimEnd().split('\n')
+
+    // search from the end to prepend `modules.` to `export[xxx]`
+    for (let i = lines.length - 1; i > 0; i--) {
+      if (lines[i].startsWith('exports')) lines[i] = 'module.' + lines[i]
+      else {
+        // at the beginning of exports, export the default function
+        lines[i] += `\nmodule.exports = ${name};`
+        break
+      }
+    }
+
+    await fs.writeFile(indexPath, lines.join('\n'))
+
+    console.log(colors.bold(`${indexPath} CJS patched`))
+  } else {
+    const matchDefault = code.match(/\nmodule.exports = (\w+);/)
+
+    if (matchDefault) {
+      code += `module.exports["default"] = ${matchDefault[1]};\n`
+      await fs.writeFile(indexPath, code)
+      console.log(colors.bold(`${indexPath} CJS patched`))
+    } else {
+      console.error(colors.red(`${indexPath} CJS patch failed`))
+      process.exit(1)
+    }
+  }
+}
diff --git a/package.json b/package.json
index e93277c..318251e 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
   },
   "scripts": {
     "dev": "unbuild --stub",
-    "build": "unbuild && tsx scripts/patchCJS.ts",
+    "build": "unbuild",
     "test": "vitest run",
     "format": "prettier --write --cache .",
     "prepublishOnly": "npm run build",
diff --git a/scripts/patchCJS.ts b/scripts/patchCJS.ts
deleted file mode 100644
index 6c916b4..0000000
--- a/scripts/patchCJS.ts
+++ /dev/null
@@ -1,53 +0,0 @@
-/**
-
-It converts
-
-```ts
-exports["default"] = viteBasicSslPlugin;
-```
-
-to
-
-```ts
-module.exports = viteBasicSslPlugin;
-module.exports["default"] = viteBasicSslPlugin;
-```
-*/
-
-import { readFileSync, writeFileSync } from 'fs'
-import colors from 'picocolors'
-
-const indexPath = 'dist/index.cjs'
-let code = readFileSync(indexPath, 'utf-8')
-
-const matchMixed = code.match(/\nexports\["default"\] = (\w+);/)
-if (matchMixed) {
-  const name = matchMixed[1]
-
-  const lines = code.trimEnd().split('\n')
-
-  // search from the end to prepend `modules.` to `export[xxx]`
-  for (let i = lines.length - 1; i > 0; i--) {
-    if (lines[i].startsWith('exports')) lines[i] = 'module.' + lines[i]
-    else {
-      // at the beginning of exports, export the default function
-      lines[i] += `\nmodule.exports = ${name};`
-      break
-    }
-  }
-
-  writeFileSync(indexPath, lines.join('\n'))
-
-  console.log(colors.bold(`${indexPath} CJS patched`))
-} else {
-  const matchDefault = code.match(/\nmodule.exports = (\w+);/)
-
-  if (matchDefault) {
-    code += `module.exports["default"] = ${matchDefault[1]};\n`
-    writeFileSync(indexPath, code)
-    console.log(colors.bold(`${indexPath} CJS patched`))
-  } else {
-    console.error(colors.red(`${indexPath} CJS patch failed`))
-    process.exit(1)
-  }
-}