diff --git a/src/esbuild.ts b/src/esbuild.ts
index 71f1e0952..26a5bb27f 100644
--- a/src/esbuild.ts
+++ b/src/esbuild.ts
@@ -1,3 +1,3 @@
-import unplugin from '.'
+import unplugin, { Options } from '.'
 
-export default unplugin.esbuild
+export default unplugin.esbuild as (options?: Options) => any;
diff --git a/src/index.ts b/src/index.ts
index f2f406bc3..330fc8fa3 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -15,7 +15,7 @@ import { join } from 'pathe'
 
 export { Options }
 
-export default createUnplugin<Options>((opt, meta) => {
+export default createUnplugin<Options>((opt = {}, meta) => {
   const options = resolveOptions(opt)
   const ctx = createRoutesContext(options)
 
diff --git a/src/rollup.ts b/src/rollup.ts
index ed6909cd3..90c0c3041 100644
--- a/src/rollup.ts
+++ b/src/rollup.ts
@@ -1,3 +1,3 @@
-import unplugin from '.'
+import unplugin, { Options } from '.'
 
-export default unplugin.rollup
+export default unplugin.rollup as (options?: Options) => any;
diff --git a/src/vite.ts b/src/vite.ts
index 589f4b964..fa6b42796 100644
--- a/src/vite.ts
+++ b/src/vite.ts
@@ -1,3 +1,3 @@
-import unplugin from '.'
+import unplugin, { Options } from '.'
 
-export default unplugin.vite
+export default unplugin.vite as (options?: Options) => any;
diff --git a/src/webpack.ts b/src/webpack.ts
index 83091ee31..713bcf9e9 100644
--- a/src/webpack.ts
+++ b/src/webpack.ts
@@ -1,3 +1,3 @@
-import unplugin from '.'
+import unplugin, { Options } from '.'
 
-export default unplugin.webpack
+export default unplugin.webpack as (options?: Options) => any;