Merge pull request #171 from AKolodeev/feat/provide-prev-state-slice

feat(connector): provide prev state slice to target (function)

Author: AntJanus

src/components/connector.js

@@ -52,8 +52,8 @@ export default function Connector(store) {
       const unsubscribe = store.subscribe(() => {
         const nextSlice = getStateSlice(store.getState(), finalMapStateToTarget);
         if (!shallowEqual(slice, nextSlice)) {
+          updateTarget(target, nextSlice, boundActionCreators, slice);
           slice = nextSlice;
-          updateTarget(target, slice, boundActionCreators);
         }
       });
       return unsubscribe;
@@ -62,9 +62,9 @@ export default function Connector(store) {
   }
 }
 
-function updateTarget(target, StateSlice, dispatch) {
+function updateTarget(target, StateSlice, dispatch, prevStateSlice) {
   if(isFunction(target)) {
-    target(StateSlice, dispatch);
+    target(StateSlice, dispatch, prevStateSlice);
   } else {
     assign(target, StateSlice, dispatch);
   }

test/components/connector.spec.js

@@ -18,7 +18,12 @@ describe('Connector', () => {
       baz: -1
     };
     store = createStore((state = defaultState, action) => {
-      return assign({}, state, { baz: action.payload });
+      switch (action.type) {
+        case 'ACTION':
+          return assign({}, state, { baz: action.payload });
+        default:
+          return state;
+      }
     });
     targetObj = {};
     connect = Connector(store);
@@ -109,4 +114,20 @@ describe('Connector', () => {
     expect(receivedDispatch).toBe(store.dispatch);
   });
 
+  it('Should provide state slice, bound actions and previous state slice to target (function)', () => {
+    const targetFunc = sinon.spy();
+
+    connect(state => state, {})(targetFunc);
+
+    expect(targetFunc.calledWith(defaultState, {}, undefined)).toBeTruthy();
+
+    store.dispatch({ type: 'ACTION', payload: 2 });
+
+    expect(targetFunc.calledWith(
+      assign({}, defaultState, { baz: 2 }),
+      {},
+      defaultState)
+    ).toBeTruthy();
+  });
+
 });