This is just part of web security Some helpful code :

1. signing jwt(sending jwt from server to client)

To achieve this:

1. const payload = { id: user.id, name: user.name };
   let token = jwt.sign(payload, process.env.SECRET, { expiresIn: '1m' });
   res.json({
   accessToken: token,
   message: "Logined succesfully"
   });
   
2. axios.post('http://localhost:3001/login', { name: name, password: pass })
   .then(response => {
   setmessage(response.data.message);
   if (response.data.accessToken) {
   localStorage.setItem("jwt", JSON.stringify({ token: response.data.accessToken }));
   }
   history.push("/");
   })
   .catch(error => console.error('There was an error!', error));
   

2. verifying jwt(sending jwt from client to server)

Method 1: work like a charm (successful or effective)

let token = localStorage.getItem("jwt");
let decodedToken = jwt_decode(token);
let currentDate = new Date();
// JWT exp is in seconds
if (decodedToken.exp * 1000 < currentDate.getTime()) {
localStorage.removeItem("jwt")
console.log("Token expired.");
return false;
} else {
console.log("Valid token");
return true;
}

Method 2:

1. function checkAuth() {
   const token = JSON.parse(localStorage.getItem("jwt")).token;
   const headers = {
   'Authorization': token
   };
   axios.get('http://localhost:3001/checkauth', { headers })
   .then(response => {
   console.log(response);
   if(response.data.message!=null)
   setmessage(response.data.message);
   else if(response.data.name!=null)
   setmessage(response.data.name);
   setTimeout(() => {
   setmessage("");
   }, 1000);
   })
   .catch(error => console.error('There was an error!', error));
   }
   

2. const token = req.headers.authorization;
   if (!token) {
   console.log("there is no token came from frontend");
   }
   else {
   jwt.verify(token, process.env.SECRET, function (err, decoded) {
   if (err) {
   console.log(err);
   res.send(err);
   }
   else {
   console.log(decoded);
   res.send(decoded);
   }
   });
   }
   

3. redirecting to private page just after clicking login submit button

To achieve this:
a. import { useHistory } from 'react-router';
b. const history = useHistory();
c. history.push("/");

4. redirecting to login page just after clicking logout submit button

To achieve this:
a. import { useHistory } from 'react-router';
b. const history = useHistory();
c. history.push("/login");