Fix flow verification errors

#130

.flowconfig

@@ -5,7 +5,6 @@
 ./src/
 
 [libs]
-./node_modules/fusion-core/flow-typed
 
 [lints]
 

flow-typed/npm/redux_v3.x.x.js

@@ -0,0 +1,94 @@
+// @flow
+// flow-typed signature: cca4916b0213065533df8335c3285a4a
+// flow-typed version: cab04034e7/redux_v3.x.x/flow_>=v0.55.x
+
+declare module 'redux' {
+  /*
+
+    S = State
+    A = Action
+    D = Dispatch
+
+  */
+
+  declare export type DispatchAPI<A> = (action: A) => A;
+  declare export type Dispatch<A: {type: $Subtype<string>}> = DispatchAPI<A>;
+
+  declare export type MiddlewareAPI<S, A, D = Dispatch<A>> = {
+    dispatch: D,
+    getState(): S,
+  };
+
+  declare export type Store<S, A, D = Dispatch<A>> = {
+    // rewrite MiddlewareAPI members in order to get nicer error messages (intersections produce long messages)
+    dispatch: D,
+    getState(): S,
+    subscribe(listener: () => void): () => void,
+    replaceReducer(nextReducer: Reducer<S, A>): void,
+  };
+
+  declare export type Reducer<S, A> = (state: S | void, action: A) => S;
+
+  declare export type CombinedReducer<S, A> = (
+    state: ($Shape<S> & {}) | void,
+    action: A
+  ) => S;
+
+  declare export type Middleware<S, A, D = Dispatch<A>> = (
+    api: MiddlewareAPI<S, A, D>
+  ) => (next: D) => D;
+
+  declare export type StoreCreator<S, A, D = Dispatch<A>> = {
+    (reducer: Reducer<S, A>, enhancer?: StoreEnhancer<S, A, D>): Store<S, A, D>,
+    (
+      reducer: Reducer<S, A>,
+      preloadedState: S,
+      enhancer?: StoreEnhancer<S, A, D>
+    ): Store<S, A, D>,
+  };
+
+  declare export type StoreEnhancer<S, A, D = Dispatch<A>> = (
+    next: StoreCreator<S, A, D>
+  ) => StoreCreator<S, A, D>;
+
+  declare export function createStore<S, A, D>(
+    reducer: Reducer<S, A>,
+    enhancer?: StoreEnhancer<S, A, D>
+  ): Store<S, A, D>;
+  declare export function createStore<S, A, D>(
+    reducer: Reducer<S, A>,
+    preloadedState?: S,
+    enhancer?: StoreEnhancer<S, A, D>
+  ): Store<S, A, D>;
+
+  declare export function applyMiddleware<S, A, D>(
+    ...middlewares: Array<Middleware<S, A, D>>
+  ): StoreEnhancer<S, A, D>;
+
+  declare export type ActionCreator<A, B> = (...args: Array<B>) => A;
+  declare export type ActionCreators<K, A> = {[key: K]: ActionCreator<A, any>};
+
+  declare export function bindActionCreators<
+    A,
+    C: ActionCreator<A, any>,
+    D: DispatchAPI<A>
+  >(
+    actionCreator: C,
+    dispatch: D
+  ): C;
+  declare export function bindActionCreators<
+    A,
+    K,
+    C: ActionCreators<K, A>,
+    D: DispatchAPI<A>
+  >(
+    actionCreators: C,
+    dispatch: D
+  ): C;
+
+  declare export function combineReducers<O: Object, A>(
+    reducers: O
+  ): CombinedReducer<$ObjMap<O, <S>(r: Reducer<S, any>) => S>, A>;
+
+  declare export var compose: $Compose;
+}

src/reducers/root.js

@@ -13,7 +13,10 @@ import error from './error';
 
 import type {State} from './types.js';
 
-export default (state: State, action: Object) => {
+export default (state?: State, action: Object) => {
+  if (!state) {
+    return {};
+  }
   return {
     count: count(state.count, action),
     rpcCount: rpcCount(state.rpcCount, action),