How can cookies be set in Next.js while using Node.js (Express) as the backend?

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You can set cookies in Next.js while using Node.js (Express) as the backend by installing the cookie-parser middleware in the Express server and using the res.cookie() method to set the cookie.

1. Install the cookie-parser middleware:

   npm install cookie-parser
   

2. Require the cookie-parser middleware in the Express server:

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

3. Use the cookie-parser middleware in the Express server:

   app.use(cookieParser());
   

4. Set a cookie in the Next.js server by sending a request to the Express server:

   // In the Next.js server
   fetch('/api/set-cookie', {
    method: 'POST',
    body: JSON.stringify({ name: 'myCookie', value: '123' }),
   });
   
   // In the Express server
   app.post('/api/set-cookie', (req, res) => {
    const { name, value } = req.body;
    res.cookie(name, value);
    res.send('Cookie set successfully!');
   });
   

5. Retrieve the cookie in the Next.js server:

   const cookies = parseCookies(req);
   const myCookie = cookies.myCookie;
   
   function parseCookies(req) {
    const cookie = req.headers.cookie;
    const cookies = {};
    if (cookie) {
      cookie.split(';').forEach((c) => {
        const [key, value] = c.trim().split('=');
        cookies[key] = value;
      });
    }
    return cookies;
   }