02_lesson: use prepare callback to customize the creation of the payload value

02_lesson_starter/src/features/posts/AddPostForm.js

@@ -1,5 +1,4 @@
 import { useState } from "react";
-import { nanoid } from "@reduxjs/toolkit";
 import { postAdded } from "./postsSlice";
 import { useDispatch } from "react-redux";
 
@@ -13,13 +12,7 @@ const AddPostForm = () => {
 
   const onSavePostClicked = () => {
     if (title && content) {
-      dispatch(
-        postAdded({
-          id: nanoid(),
-          title,
-          content,
-        })
-      );
+      dispatch(postAdded(title, content));
       setTitle("");
       setContent("");
     }

02_lesson_starter/src/features/posts/postsSlice.js

@@ -1,4 +1,4 @@
-import { createSlice } from "@reduxjs/toolkit";
+import { createSlice, nanoid } from "@reduxjs/toolkit";
 
 const initialState = [
   {
@@ -17,8 +17,19 @@ const postsSlice = createSlice({
   name: "posts",
   initialState,
   reducers: {
-    postAdded(state, action) {
-      state.push(action.payload); // immer.js add new payload without mutation
+    postAdded: {
+      reducer: (state, action) => {
+        state.push(action.payload);
+      },
+      prepare(title, content) {
+        return {
+          payload: {
+            id: nanoid(),
+            title,
+            content,
+          },
+        };
+      },
     },
   },
 });