Ivana-/index.html

## index.html
<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
      .unauthorized-display-none { display: none }
      .authorized-display-none { display: none }
    </style>
  </head>
  <body>
    <div class="unauthorized-display-none">
      <span><a href="/login">Войти</a></span>
      <span><a href="/register">Зарегистрироваться</a></span>
    </div>
    <div class="authorized-display-none">
      <span id="user-login"></span>
      <span><a href="/logout">Выйти</a></span> <!-- Тут надо кнопку с фетчем POST! -->
    </div>
    <!-- Other elements -->
    <p class="authorized-display-none"><a href="/app">Контент для авторизованных</a> в полной версии.</p>
    <script>
      async function fetchProcessUserData() {
        const resp = await fetch("/user-data", { method: "GET" })
        authorized = false
        if (resp.ok) {
          const data = await resp.json()
          if (data) {
            const { login, created } = data
            const elem = document.getElementById("user-login")
            elem.textContent = login
            authorized = true
          }
        }
        const tag = authorized ? "authorized-display-none" : "unauthorized-display-none"
        const elements = document.getElementsByClassName(tag)
        for (let i = elements.length - 1; i >= 0; i--) elements[i].classList.toggle(tag)
      }
      fetchProcessUserData()
    </script>
  </body>
</html>
	<!doctype html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<style>
	.unauthorized-display-none { display: none }
	.authorized-display-none { display: none }
	</style>
	</head>
	<body>
	<div class="unauthorized-display-none">
	<span><a href="/login">Войти</a></span>
	<span><a href="/register">Зарегистрироваться</a></span>
	</div>
	<div class="authorized-display-none">
	<span id="user-login"></span>
	<span><a href="/logout">Выйти</a></span> <!-- Тут надо кнопку с фетчем POST! -->
	</div>
	<!-- Other elements -->
	<p class="authorized-display-none"><a href="/app">Контент для авторизованных</a> в полной версии.</p>
	<script>
	async function fetchProcessUserData() {
	const resp = await fetch("/user-data", { method: "GET" })
	authorized = false
	if (resp.ok) {
	const data = await resp.json()
	if (data) {
	const { login, created } = data
	const elem = document.getElementById("user-login")
	elem.textContent = login
	authorized = true
	}
	}
	const tag = authorized ? "authorized-display-none" : "unauthorized-display-none"
	const elements = document.getElementsByClassName(tag)
	for (let i = elements.length - 1; i >= 0; i--) elements[i].classList.toggle(tag)
	}
	fetchProcessUserData()
	</script>
	</body>
	</html>