Is it not possible to set cookies in Next.js when using Node.js (Express) as the backend?

edit

It is possible to set cookies in Next.js when using Node.js (Express) as the backend. You can use the cookie-parser middleware in your Express server to parse and set cookies.

Here's an example code snippet:

// server.js

const express = require('express')
const cookieParser = require('cookie-parser')

const app = express()

app.use(cookieParser())

app.get('/', (req, res) => {
  res.cookie('myCookie', 'hello world', { maxAge: 900000, httpOnly: true })
  res.send('Cookie set!')
})

module.exports = app

In the above code, we're setting the myCookie cookie with a value of 'hello world'. The maxAge parameter determines how long the cookie will persist (in milliseconds), and the httpOnly parameter ensures that the cookie can only be accessed via HTTP requests (i.e. not via JavaScript).

Once the cookie is set, you can access it in your Next.js app by using the getInitialProps method:

// pages/index.js

import fetch from 'isomorphic-unfetch'

const Index = ({ myCookie }) => {
  return (
    <div>
      <p>The value of myCookie is: {myCookie}</p>
    </div>
  )
}

Index.getInitialProps = async ({ req }) => {
  const res = await fetch('http://localhost:3000')
  const myCookie = req.headers.cookie.split('=')[1]
  return { myCookie }
}

export default Index

In the above component, we're using fetch to make a request to the Express server and retrieve the myCookie value from the req.headers.cookie header. We can then pass this value as a prop to our component.