how to jwt token verify using nodejs - node.js

Question

how to implement jwt verify token implement in node js.I already tried but its not showing error but its showing undefined.How to solve this issue.
auth.py
function jwtAccessAuthCheck(accessToken)
{
if(accessToken)
{
console.log("Sucess")
jwt.verify(accessToken,"secretkey",function(err){
if(err) {
console.log(typeof(err.message))
return err.message
}
else {
return "token"
}
});
}
else
{
return "Invalid token"
}
}
routes.py
//Get Data from Database
router.get('/', async (req, res,next) => {
(async function() {
try {
await client.connect();
console.log("Connected correctly to server");
const db = client.db('olc_prod_db');
const token_validation = validate_token.validate_token(req.headers.authorization)
console.log((token_validation))
const r = await db.collection('Ecommerce').find().toArray();
client.close();
res.send(r)
} catch(err) {
console.log(err.stack);
}
})();
});

Answer 1

const express = require('express');
const app = express();
const jwt = require('jsonwebtoken');
const bodyparser = require('body-parser');
const user = {username : "user",password : "pass"}
app.use(bodyparser.json());
const checkToken = function (req,res,next)
{
const header = req.headers['authorization'];
if(typeof header !== 'undefined')
{
const bearer = header.split(' ');
const token = bearer[1];
req.token=token;
next();
}
else
{
res.sendStatus(403);
}
}
app.post('/login',function (req,res)
{
const { body } = req;
const { username } = body;
const { password } = body;
if(username === user.username && password === user.password)
{
jwt.sign({user},'privatekey',{expiresIn : '1h'},function (err,token){
if(err)
{
console.log(err)
}
console.log(token);
res.end();
});
}
else
{
console.log('Error : Could not log in');
}
});
app.get('/data',checkToken,function(req,res)
{
jwt.verify(req.token,'privatekey',function (err,authorizedata)
{
if(err)
{
console.log('Error : Could not connect to the protected route');
res.sendStatus(403);
}
else
{
res.json({
message : 'Successful log in',
authorizedata
});
console.log('Success : Connected to protected route');
}
});
});
app.listen(3000,console.log("Server is running at 3000"));
This is how I have implemented JWT token