NextJS Redux ReactJS

Pre-requisites -

Basic knowledge about how to use Redux and Redux Toolkit.
How Next js works, the difference between server and client-side components.
Usability of Chrome developer tools.

Procedure -

Installation - Make your next js app by running the command below in the terminal and then install the packages - react-redux, @reduxjs/toolkit.
```
 npx create-next-app@latest
 cd my-app
 npm i react-redux @reduxjs/toolkit
```
Folder Structure - In our app folder we have created a redux folder containing two files store.js which will be our store configuration and Provider.js in which we will create a provider component. For easy differentiation, we have a client folder containing the client component and a server folder containing the server component.

Mode - We will create a redux store code which will be used to toggle the mode of our theme between light and dark at the click of a button and see how server and client components differ. Also, start the server by running the command. npm run dev in the terminal.

Code -

Code for the redux/store.js file

"use client"
import { createSlice, configureStore } from "@reduxjs/toolkit"

const state = {
    theme : "light",
}
const themeMode = createSlice({
    name : "theme",
    initialState : state,
    reducers : {
        toggle : (initialState, e)=>{
            return {...initialState, theme : e.payload}
        }
    }
})
export const {toggle} = themeMode.actions;
const store = configureStore({
    reducer : {
        themeMode : themeMode.reducer,
    }
})
export default store;

Code for redux/Provider.js

"use client"

import { Provider } from "react-redux"
import store from "./store"

export default function Provider({children}) {
    return (
        <>
        <Provider store={store}>
        {children}
        </Provider>
        </>
    )
}

Why do we need a Provider.js file?

As we know that redux works on the client side but we also know that by default all the components of next js are by default server-side components so we need a new component that is a client-side use provider from redux in it and then wrap that new Provider component around the layout.js file in the app folder.

Structure of app/layout.js

import './globals.css'
import { Inter } from 'next/font/google'
import Provider from './redux/Provider'

const inter = Inter({ subsets: ['latin'] })

export const metadata = {
  title: 'Create Next App',
  description: 'Generated by create next app',
}

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body className={inter.className}>
        <Provider>
        {children}
        </Provider>
        </body>
    </html>
  )
}

Many of you might doubt, like as we are wrapping a client-side Provider component along all the children (i.e combination of server-side and client-side components) does this make all the components client-side?

The answer is no, server components are only handled as client components when they are directly imported and rendered in a client component (that has 'use client'). We can verify it on our server-side page by doing console.log and you will see that it logs to the server, not in the browser console.

Code for client/page.js

"use client"

import { useDispatch, useSelector } from "react-redux"
import { toggle } from "../redux/store";

export default function page() {

    const dispatch = useDispatch();
    const theme = useSelector((state)=>state.themeMode.theme);

  return (
    <div className="">
        {theme}
        <button onClick={()=>{
            if (theme=="light") {
                dispatch(toggle("dark"))
            } else {
                dispatch(toggle("light"))
            }
        }}>Toggle</button>
    </div>
  )
}

Browser output -

https://youtu.be/0sOo1RJTJvw

Follow -

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Redux in NextJS

Pre-requisites -

Procedure -

Code -

Why do we need a Provider.js file?

Follow -