udemy-go-web-2/static/js/base.js

let loginLink = document.getElementById("login-link");
let vtLink = document.getElementById("vt-link");

document.addEventListener("DOMContentLoaded", function () {
    if (localStorage.getItem("token") !== null) {
        loginLink.innerHTML = '<a href="#!" onclick="logout()" class="nav-link">Logout</a>';
        vtLink.classList.remove('d-none');
    } else {
        loginLink.innerHTML = '<a href="/login" class="nav-link">Login</a>';
    }
    loginLink.classList.remove('d-none')
});

function logout() {
    localStorage.removeItem("token");
    localStorage.removeItem("token_expiry");
    location.href = "/logout";
}