Add basic version of post show page

app/javascript/reducers/postReducer.ts

@@ -1,3 +1,13 @@
+import {
+  POST_REQUEST_START,
+  POST_REQUEST_SUCCESS,
+  POST_REQUEST_FAILURE,
+} from '../actions/requestPost';
+
+import {
+  CHANGE_POST_STATUS_SUCCESS,
+} from '../actions/changePostStatus';
+
 import IPost from '../interfaces/IPost';
 
 const initialState: IPost = {
@@ -15,7 +25,7 @@ const postReducer = (
   action,
 ): IPost => {
   switch (action.type) {
-    case 'CONVERT':
+    case POST_REQUEST_SUCCESS:
       return {
         id: action.post.id,
         title: action.post.title,
@@ -26,6 +36,14 @@ const postReducer = (
         createdAt: action.post.created_at,
       };
 
+    case CHANGE_POST_STATUS_SUCCESS:
+      return {
+        ...state,
+        postStatusId: action.newPostStatusId,
+      };
+
+    case POST_REQUEST_START:
+    case POST_REQUEST_FAILURE:
     default:
       return state;
   }