diff --git a/src/useSetState.ts b/src/useSetState.ts
index 2ec750a8..3e44e0fd 100644
--- a/src/useSetState.ts
+++ b/src/useSetState.ts
@@ -3,8 +3,7 @@ import {useState} from 'react';
 const useSetState = <T extends object>(initialState: T = {} as T): [T, (patch: Partial<T> | Function) => void]=> {
   const [state, set] = useState<T>(initialState);
   const setState = patch => {
-    if (patch instanceof Function) set(prevState => Object.assign({}, prevState, patch(prevState)));
-    else set(Object.assign({}, state, patch));
+    set(prevState => Object.assign({}, prevState, patch instanceof Function ? patch(prevState) : patch));
   };
 
   return [state, setState];