- implementing immutable.js

app/reducers/activeEvent.js

@@ -0,0 +1,12 @@
+import { SET_ACTIVE_EVENT, UNSET_ACTIVE_EVENT } from '../constants/actionTypes.js';
+
+export const activeEvent = (state = null, action) => {
+  switch (action.type) {
+    case SET_ACTIVE_EVENT:
+      return action.payload;
+    case UNSET_ACTIVE_EVENT:
+      return null;
+    default:
+      return state;
+  }
+};