diff --git a/types/redux-localstorage/index.d.ts b/types/redux-localstorage/index.d.ts
index b4af824d9b..b788fcd963 100644
--- a/types/redux-localstorage/index.d.ts
+++ b/types/redux-localstorage/index.d.ts
@@ -26,4 +26,6 @@ export function mergePersistedState(merge?: <A1, A2>(initialState: A1, persisten
 
 export default function persistState<A>(storage?: StorageAdapter<A>, key?: string, callback?: Function): Redux.GenericStoreEnhancer;
 
+export function transformState<A1, A2>(down: ((state: A1) => A2) | Array<(state: any) => any>, up: ((state: A2) => A1) | Array<(state: any) => any>): (storage: StorageAdapter<A1>) => A2;
+
 export const actionTypes: ActionTypes;
diff --git a/types/redux-localstorage/redux-localstorage-tests.ts b/types/redux-localstorage/redux-localstorage-tests.ts
index 49bf442fcf..17f453423a 100644
--- a/types/redux-localstorage/redux-localstorage-tests.ts
+++ b/types/redux-localstorage/redux-localstorage-tests.ts
@@ -2,6 +2,7 @@ import { Reducer, compose, combineReducers, createStore } from "redux";
 import {
     default as persistState,
     mergePersistedState,
+    transformState,
     actionTypes
 } from "redux-localstorage";
 import * as adapterAsyncStorage from "redux-localstorage/lib/adapters/AsyncStorage";
@@ -31,3 +32,7 @@ const createStoreLocalStorage = compose(
 const createStoreSessionStorage = compose(
     persistState(storageSessionStorage, "foo")
 )(createStore)(reducer);
+
+const storage = compose(
+    transformState([JSON.stringify, btoa], [atob, JSON.parse])
+)(storageLocalStorage);