firebase auth attempt with svelte kit

__layout.svelte

<script context="module" lang="ts">
	import { authGuard } from '../auth/guard';
	import type { LoadInput, LoadOutput } from '@sveltejs/kit/types/page';

	export async function load({ page, fetch, session, context }: LoadInput): Promise<LoadOutput> {
		return await authGuard({ page, fetch, session, context });
	}
</script>

<script lang="ts">
	import '../app.postcss';
</script>

<div class="bg-gray-100 h-screen">
	<div class="mx-auto max-w-xl bg-white rounded shadow">
		<header>
			<div class="p-2 bg-indigo-800 text-center text-white">HEADER</div>
		</header>
		<div class="py-2 px-1">
			<slot />
		</div>
	</div>
</div>

auth.ts

import type { User } from "firebase/auth";
import { writable } from "svelte/store";

export interface AuthState {
	user: User | null
}

export const authStore = writable<AuthState>({ user: null })

firebase.ts

import { getAuth, onAuthStateChanged, Auth, signInWithEmailAndPassword, signOut as fbsignout } from "firebase/auth";
import { initializeApp } from "firebase/app"
import { browser } from "$app/env";
import { authStore } from "../stores/auth";

const firebaseConfig = {
    /// ...
};

let auth: Auth;

// initialize firebase
if (browser) {
    const firebaseApp = initializeApp(firebaseConfig);
    auth = getAuth(firebaseApp);
    onAuthStateChanged(auth, user => {
        console.log("user:", user);
        authStore.set({ user: user })
    });
}

export async function signIn(email: string, password: string): Promise<boolean> {
    try {
        await signInWithEmailAndPassword(auth, email, password)
        return true;
    } catch (err) {
        console.log("error: signIn:", err);
        return false;
    }
}

export async function signOut(): Promise<boolean> {
    try {
        await fbsignout(auth);
        return true;
    } catch (err) {
        console.log("error: signout:", err);
        return false;
    }
}

guard.ts

import type { LoadInput, LoadOutput } from '@sveltejs/kit/types/page';
import { authStore } from '../stores/auth';

export async function authGuard({ page }: LoadInput): Promise<LoadOutput> {

    let isLoggedIn = false;
    authStore.subscribe(store => {
        store.user ? true : false;
    })

    console.log(page.path)

    if (!isLoggedIn && page.path.startsWith('/app')) {
        return { status: 302, redirect: '/auth' }
    }

    return {};
}

export default {
    authGuard
}