Best practices for care some routes handler

I know that is possible to implement the authentication logic at the beginning of each route handler. In the following code the protected routes should only be visible after the user authentication. My concern is about the best pratices to care some routes handler.

Is this the best approach to implement a separation between public and protected routes handler?

<script>
  import { Router, Route, navigate } from "svelte-routing";
  import NavLink from "./components/NavLink.svelte";
  import Home from "./routes/Home.svelte";
  import About from "./routes/About.svelte";
  import Login from "./routes/Login.svelte";
  import { currentUser } from "./stores/current_user.js";

  // Used for SSR. A falsy value is ignored by the Router.
  export let url = "";

  let showNav = false;

 $: if ($currentUser.token) {
      showNav = true
      navigate("/", { replace: true });
  } else {
      showNav = false
      navigate("/login", { replace: true });
  }

</script>

<Router url="{url}">

{#if showNav}
 <nav>
    <NavLink to="/">Home</NavLink>
    <NavLink to="about">About</NavLink>
  </nav>
{/if}

 <div>
    <Route path="/" component="{Home}" />
    <Route path="/about" component="{About}" />
    <Route path="/login" component="{Login}" />
  </div>

</Router>

[mefechoel]

Hmm, you could try to put the call to navigate in an onMount. Navigations that occure before the main Router’s mounting are swallowed (see related issue in svelte-navigator). The problem is, that you’ll loose the reactivity in onMount. So afterUpdate might be the better place to put it. But because your component is always rendered, it will redirect on every route, when the user isn’t logged in. That’s why I put the guard in a second component inside the Route. That way, it is only rendered whe the route matches and only then redirects.

[sayhicoelho]

I’d like to see beforeEnter to run some piece of code whenever routing starts.