JWT using middleware in nextjs

auth.js

// Under /lib folder of the frontend

import { jwtVerify, SignJWT } from 'jose' 21.6k (gzipped: 6.6k)

export const getJwtSecretKey () => {
const secret = process.env. JWT_SECRET_KEY;
  
  
if (!s ret || secret.length == 0)
throw new Error('The environment variable JWT_SECRET KEY is not set.')
}
return secret
}
export const verifyAuth = async (token) => {
try {
const verified = await jwtVerify (token, new TextEncoder ().encode (getJwtSecretKey()))
return verified.payload 
} catch (error) {
throw new Error('Your token has expired.')
}
}

login.js

// API route under /api folder
import { SignJWT } from 'jose'
import { nanoid } from 'nanoid'
import cookie from 'cookie'

export const getJwtSecretKey () => {
const secret = process.env. JWT_SECRET_KEY;

const authRouter = (req, res) => {
 const { email, password } = JSON.parse(req.body);
  
  if (email === process.env.ADMIN_EMAIL && password === process.env.ADMIN_PASSWORD) {
// user is logged in successfully
// return a jwt cookie to the user
const token = await new SignJWT({})
.setProtectedHeader({ alg: 'HS256' })
.setJti(nanoid())
.setIssuedAt()
.setExpiration Time ('1m')
.sign(new TextEncoder ().encode (getJwtSecretKey()))
res.setHeader (
'Set-Cookie',
cookie.serialize('user-token', token, {
httpOnly: true,
path: '/',
secure: process.env.NODE_ENV === 'production',
})
  
}

middleware.js

import { NextRequest, NextResponse } from 'next/server' 
import {verifyAuth} from './lib/auth'

export async function middleware(req: NextRequest) {
const token = req.cookies.get('user-token')?.value
const verifiedToken =
token &&
(await verifyAuth(token).catch((err) => {
console.log(err)
}))
if (req.nextUrl.pathname.startsWith('/login') && !verifiedToken
return
}
URL (url: string
if(req.url.includes('/login') && verifiedToken !== undefined):
return NextResponse.redirect(new URL('/dashboard', req.url))
}
if (!verifiedToken) {
return NextResponse.redirect (new URL('/login', req.url))
}
}

export const config = {
matcher: ['/dashboard', '/login'],
}