From ca83e39b6f48f898189e44eb97daec04f7259f6b Mon Sep 17 00:00:00 2001
From: Anthony Fu <anthonyfu117@hotmail.com>
Date: Tue, 13 Jul 2021 00:13:13 +0800
Subject: [PATCH] fix: update type

---
 src/types.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/types.ts b/src/types.ts
index aba7388a..0c1ce7a9 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,8 +1,10 @@
 import { Plugin as RollupPlugin } from 'rollup'
 
+export type Thenable<T> = T | Promise<T>
+
 export interface UnpluginHooks {
   transformInclude?: (id: string) => boolean;
-  transform?: (code: string, id: string) => string | { code: string; map: any; };
+  transform?: (code: string, id: string) => Thenable<string | { code: string; map: any; } | null | undefined>;
 }
 
 export interface UnpluginOptions<UserOptions> {