Accept new state as the return value of action case

examples/message.js

@@ -7,14 +7,16 @@ import * as duck from '../src/duck';
 // -------------------------------------
 
 const UPDATE = duck.defineType('message', 'UPDATE');
+const RESET = duck.defineType('message', 'RESET');
 
 // -------------------------------------
 //   Actions
 // -------------------------------------
 
 const updateAction = duck.createAction(UPDATE);
+const reset = duck.createAction(RESET);
 
-// Dispatch action
+// Dispatch action in anywhere
 // dispatch(updateAction('hello world!'));
 
 // -------------------------------------
@@ -30,8 +32,11 @@ const initState: State = {
 };
 
 export default duck.createReducer(initState, {
-  UPDATE: (state, action) => {
-    // `state.message` should be 'hello world!'
+  [UPDATE]: (state, action) => {
+    // message should turn to 'hello world!'
     state.message = action.payload;
   },
+  [RESET]: () => {
+    return initState;
+  },
 });

package.json

@@ -1,6 +1,6 @@
 {
   "name": "redux-duck-immer",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description":
     "Providing redux helpers to implement ducks-modular-redux proposal and Immer for immutability",
   "repository": "git@github.com:cjies/redux-duck-immer.git",

src/duck.js

@@ -61,7 +61,7 @@ export function createReducer<S, P: any>(
   return (state: S = initState, action: Action<P>): S => {
     return produce(state, (draftState: S): void | S => {
       if (action && cases[action.type]) {
-        cases[action.type](draftState, action);
+        return cases[action.type](draftState, action);
       }
     });
   };

src/duck.test.js

@@ -55,17 +55,25 @@ test('create action creator', t => {
 
 test('create reducer', t => {
   const UPDATE_MESSAGE = duck.defineType('UPDATE_MESSAGE');
-  const updateMessage = {
-    type: UPDATE_MESSAGE,
-    payload: 'hello world',
-  };
+  const RESET = duck.defineType('RESET');
+
+  function updateMessage(message) {
+    return {
+      type: UPDATE_MESSAGE,
+      payload: message,
+    };
+  }
+  const reset = duck.createAction(RESET);
 
   const initState = {
     message: '',
   };
   const testReducer = duck.createReducer(initState, {
-    [UPDATE_MESSAGE]: (state, action) => {
-      state.message = action.payload;
+    [UPDATE_MESSAGE]: (state, { payload }) => {
+      state.message = payload;
+    },
+    [RESET]: () => {
+      return initState;
     },
   });
 
@@ -77,7 +85,8 @@ test('create reducer', t => {
     'the reducer should be able to return the default state'
   );
 
-  const testState = testReducer({}, updateMessage);
+  const testState = testReducer({}, updateMessage('hello world'));
+  const testState2 = testReducer(testState, reset());
 
   t.deepEqual(
     testState,
@@ -86,6 +95,14 @@ test('create reducer', t => {
     },
     'the reducer should work with the defined cases'
   );
+
+  t.deepEqual(
+    testState2,
+    {
+      message: '',
+    },
+    'the reducer should work with the defined cases'
+  );
 });
 
 // Reducer state