User Authentication using JWT (JSON Web Token) with Node.js code example

Example: jwt implementation in node js

const jwt = require("jsonwebtoken")

const jwtKey = "my_secret_key"
const jwtExpirySeconds = 300

const users = {
	user1: "password1",
	user2: "password2",
}

const signIn = (req, res) => {
	// Get credentials from JSON body
	const { username, password } = req.body
	if (!username || !password || users[username] !== password) {
		// return 401 error is username or password doesn't exist, or if password does
		// not match the password in our records
		return res.status(401).end()
	}

	// Create a new token with the username in the payload
	// and which expires 300 seconds after issue
	const token = jwt.sign({ username }, jwtKey, {
		algorithm: "HS256",
		expiresIn: jwtExpirySeconds,
	})
	console.log("token:", token)

	// set the cookie as the token string, with a similar max age as the token
	// here, the max age is in milliseconds, so we multiply by 1000
	res.cookie("token", token, { maxAge: jwtExpirySeconds * 1000 })
	res.end()
}