How to check if user is authenticated on SvelteKit

SvelteKit is a powerful framework for building web applications with Svelte. When working on an application that requires authentication, it’s important to be able to check if a user is authenticated or not. In this blog post, we’ll explore different ways to achieve this in SvelteKit.

Solution 1: Using a writable store

One way to check if a user is authenticated in SvelteKit is by using a writable store. A writable store allows you to create a value that can be updated from anywhere in your application. Here’s how you can implement this:

// stores/auth.js

import { writable } from 'svelte/store';

export const isAuthenticated = writable(false);

// components/Navbar.svelte




  {#if $isAuthenticated}
    Welcome, user!
  {:else}
    Please log in.
  {/if}

In the code above, we create a writable store called isAuthenticated in the stores/auth.js file. We initialize it with a default value of false. In the Navbar.svelte component, we import the isAuthenticated store and use it in an if block to conditionally render the appropriate content based on the user’s authentication status.

Solution 2: Using session variables

Another approach to check if a user is authenticated in SvelteKit is by using session variables. SvelteKit provides a built-in session store that allows you to store data that persists across requests. Here’s how you can implement this:

// components/Login.svelte





// components/Navbar.svelte




  {#if $session.user}
    Welcome, {$session.user.name}!
  {:else}
    Please log in.
  {/if}

In the code above, we have a Login.svelte component that handles the login functionality. When the user clicks the “Log in” button, we make an API call to the login function, which returns the user object. We then store the user object in the session store using $session.user = user;. In the Navbar.svelte component, we import the session store and use it in an if block to conditionally render the appropriate content based on the presence of the user object in the session.

These are two common approaches to check if a user is authenticated in SvelteKit. You can choose the one that best suits your application’s needs. Happy coding!

How to check if user is authenticated on SvelteKit