diff --git a/src/types.ts b/src/types.ts
index c49301f3c..072df0772 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -90,11 +90,20 @@ export type Mutator<Data = any> = (
   shouldRevalidate?: boolean
 ) => Promise<Data | undefined>
 
-export type ScopedMutator<Data> = (
-  key: Key,
-  data?: Data | Promise<Data> | MutatorCallback<Data>,
-  shouldRevalidate?: boolean
-) => Promise<Data | undefined>
+export interface ScopedMutator<Data = any> {
+  /** This is used for bound mutator */
+  (
+    key: Key,
+    data?: Data | Promise<Data> | MutatorCallback<Data>,
+    shouldRevalidate?: boolean
+  ): Promise<Data | undefined>
+  /** This is used for global mutator */
+  <T = any>(
+    key: Key,
+    data?: T | Promise<T> | MutatorCallback<T>,
+    shouldRevalidate?: boolean
+  ): Promise<T | undefined>
+}
 
 export type KeyedMutator<Data> = (
   data?: Data | Promise<Data> | MutatorCallback<Data>,
diff --git a/src/use-swr.ts b/src/use-swr.ts
index 35fd4a68e..70ba71fa3 100644
--- a/src/use-swr.ts
+++ b/src/use-swr.ts
@@ -700,7 +700,8 @@ Object.defineProperty(SWRConfig, 'default', {
 export const mutate = internalMutate.bind(
   null,
   defaultConfig.cache
-) as ScopedMutator<any>
+) as ScopedMutator
+
 export function createCache<Data>(
   provider: Cache
 ): {
@@ -713,5 +714,4 @@ export function createCache<Data>(
     mutate: internalMutate.bind(null, cache) as ScopedMutator<Data>
   }
 }
-
 export default useSWR