Getting Started

Build a User Management App with SvelteKit

This tutorial demonstrates how to build a basic user management app. The app authenticates and identifies the user, stores their profile information in the database, and allows the user to log in, update their profile details, and upload a profile photo. The app uses:

  • Supabase Database - a Postgres database for storing your user data and Row Level Security so data is protected and users can only access their own information.
  • Supabase Auth - users log in through magic links sent to their email (without having to set up passwords).
  • Supabase Storage - users can upload a profile photo.

Supabase User Management example

Project setup

Before we start building we're going to set up our Database and API. This is as simple as starting a new Project in Supabase and then creating a "schema" inside the database.

Create a project

  1. Create a new project in the Supabase Dashboard.
  2. Enter your project details.
  3. Wait for the new database to launch.

Set up the database schema

Now we are going to set up the database schema. We can use the "User Management Starter" quickstart in the SQL Editor, or you can just copy/paste the SQL from below and run it yourself.

  1. Go to the SQL Editor page in the Dashboard.
  2. Click User Management Starter.
  3. Click Run.

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supabase link --project-ref <project-id>
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# You can get <project-id> from your project's dashboard URL: https://supabase.com/dashboard/project/<project-id>
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supabase db pull

Get the API Keys

Now that you've created some database tables, you are ready to insert data using the auto-generated API. We just need to get the Project URL and anon key from the API settings.

  1. Go to the API Settings page in the Dashboard.
  2. Find your Project URL, anon, and service_role keys on this page.

Building the app

Let's start building the Svelte app from scratch.

Initialize a Svelte app

We can use the SvelteKit Skeleton Project to initialize an app called supabase-sveltekit (for this tutorial we will be using TypeScript):


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npm create svelte@latest supabase-sveltekit
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cd supabase-sveltekit
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npm install

Then install the Supabase client library: supabase-js


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npm install @supabase/supabase-js

And finally we want to save the environment variables in a .env. All we need are the SUPABASE_URL and the SUPABASE_KEY key that you copied earlier.

.env

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PUBLIC_SUPABASE_URL="YOUR_SUPABASE_URL"
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PUBLIC_SUPABASE_ANON_KEY="YOUR_SUPABASE_KEY"

Optionally, add src/styles.css with the CSS from the example.

Creating a Supabase client for SSR:

The ssr package configures Supabase to use Cookies, which is required for server-side languages and frameworks.

Install the Supabase packages:


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npm install @supabase/ssr @supabase/supabase-js

Creating a Supabase client with the ssr package automatically configures it to use Cookies. This means your user's session is available throughout the entire SvelteKit stack - page, layout, server, hooks.

Add the code below to your src/hooks.server.ts to initialize the client on the server:

src/hooks.server.ts

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// src/hooks.server.ts
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import { PUBLIC_SUPABASE_URL, PUBLIC_SUPABASE_ANON_KEY } from '$env/static/public'
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import { createServerClient } from '@supabase/ssr'
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import type { Handle } from '@sveltejs/kit'
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export const handle: Handle = async ({ event, resolve }) => {
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event.locals.supabase = createServerClient(PUBLIC_SUPABASE_URL, PUBLIC_SUPABASE_ANON_KEY, {
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cookies: {
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get: (key) => event.cookies.get(key),
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/**
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* Note: You have to add the `path` variable to the
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* set and remove method due to sveltekit's cookie API
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* requiring this to be set, setting the path to `/`
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* will replicate previous/standard behaviour (https://kit.svelte.dev/docs/types#public-types-cookies)
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*/
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set: (key, value, options) => {
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event.cookies.set(key, value, { ...options, path: '/' })
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},
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remove: (key, options) => {
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event.cookies.delete(key, { ...options, path: '/' })
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},
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},
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})
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/**
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* Unlike `supabase.auth.getSession()`, which returns the session _without_
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* validating the JWT, this function also calls `getUser()` to validate the
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* JWT before returning the session.
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*/
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event.locals.safeGetSession = async () => {
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const {
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data: { session },
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} = await event.locals.supabase.auth.getSession()
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if (!session) {
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return { session: null, user: null }
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}
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const {
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data: { user },
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error,
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} = await event.locals.supabase.auth.getUser()
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if (error) {
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// JWT validation has failed
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return { session: null, user: null }
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}
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return { session, user }
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}
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return resolve(event, {
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filterSerializedResponseHeaders(name) {
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return name === 'content-range' || name === 'x-supabase-api-version'
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},
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})
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}

If you are using TypeScript the compiler might complain about event.locals.supabase and event.locals.safeGetSession, this can be fixed by updating your src/app.d.ts with the content below:

src/app.d.ts

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// src/app.d.ts
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import { SupabaseClient, Session } from '@supabase/supabase-js'
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declare global {
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namespace App {
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interface Locals {
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supabase: SupabaseClient
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safeGetSession(): Promise<{ session: Session | null; user: User | null }>
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}
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interface PageData {
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session: Session | null
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user: User | null
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}
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// interface Error {}
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// interface Platform {}
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}
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}

Create a new src/routes/+layout.server.ts file to handle the session on the server-side.

src/routes/+layout.server.ts

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// src/routes/+layout.server.ts
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import type { LayoutServerLoad } from './$types'
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export const load = (async ({ locals: { safeGetSession } }) => {
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const { session, user } = await safeGetSession()
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return {
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session,
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user,
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}
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}) satisfies LayoutServerLoad

Create a new src/routes/+layout.ts file to handle the session and the supabase object on the client-side.

src/routes/+layout.ts

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// src/routes/+layout.ts
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import { PUBLIC_SUPABASE_ANON_KEY, PUBLIC_SUPABASE_URL } from '$env/static/public'
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import type { LayoutLoad } from './$types'
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import { createBrowserClient, isBrowser, parse } from '@supabase/ssr'
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export const load = (async ({ fetch, data, depends }) => {
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depends('supabase:auth')
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const supabase = createBrowserClient(PUBLIC_SUPABASE_URL, PUBLIC_SUPABASE_ANON_KEY, {
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global: {
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fetch,
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},
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cookies: {
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get(key) {
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if (!isBrowser()) {
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return JSON.stringify(data.session)
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}
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const cookie = parse(document.cookie)
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return cookie[key]
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},
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},
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})
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/**
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* It's fine to use `getSession` here, because on the client, `getSession` is
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* safe, and on the server, it reads `session` from the `LayoutData`, which
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* safely checked the session using `safeGetSession`.
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*/
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const {
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data: { session },
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} = await supabase.auth.getSession()
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return { supabase, session }
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}) satisfies LayoutLoad

Update your src/routes/+layout.svelte:

src/routes/+layout.svelte

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<!-- src/routes/+layout.svelte -->
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<script lang="ts">
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import '../styles.css'
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import { invalidate } from '$app/navigation'
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import { onMount } from 'svelte'
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export let data
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let { supabase, session } = data
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$: ({ supabase, session } = data)
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onMount(() => {
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const { data } = supabase.auth.onAuthStateChange((event, _session) => {
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if (_session?.expires_at !== session?.expires_at) {
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invalidate('supabase:auth')
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}
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})
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return () => data.subscription.unsubscribe()
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})
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</script>
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<svelte:head>
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<title>User Management</title>
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</svelte:head>
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<div class="container" style="padding: 50px 0 100px 0">
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<slot />
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</div>

Set up a login page

Supabase Auth UI

We can use the Supabase Auth UI, a pre-built Svelte component, for authenticating users via OAuth, email, and magic links.

Install the Supabase Auth UI for Svelte


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npm install @supabase/auth-ui-svelte @supabase/auth-ui-shared

Add the Auth component to your home page

src/routes/+page.svelte

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<!-- src/routes/+page.svelte -->
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<script lang="ts">
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import { Auth } from '@supabase/auth-ui-svelte'
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import { ThemeSupa } from '@supabase/auth-ui-shared'
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export let data
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</script>
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<svelte:head>
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<title>User Management</title>
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</svelte:head>
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<div class="row flex-center flex">
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<div class="col-6 form-widget">
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<Auth
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supabaseClient={data.supabase}
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view="magic_link"
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redirectTo={`${data.url}/auth/callback`}
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showLinks={false}
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appearance={{ theme: ThemeSupa, style: { input: 'color: #fff' } }}
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/>
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</div>
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</div>

Create a src/routes/+page.server.ts file that will return our website URL to be used in our redirectTo above.


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// src/routes/+page.server.ts
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import { redirect } from '@sveltejs/kit'
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import type { PageServerLoad } from './$types'
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export const load: PageServerLoad = async ({ url, locals: { safeGetSession } }) => {
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const { session } = await safeGetSession()
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// if the user is already logged in return them to the account page
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if (session) {
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redirect(303, '/account')
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}
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return { url: url.origin }
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}

Proof Key for Code Exchange (PKCE)

As we are employing Proof Key for Code Exchange (PKCE) in our authentication flow, it is necessary to create a server endpoint responsible for exchanging the code for a session.

In the following code snippet, we perform the following steps:

  • Retrieve the code sent back from the Supabase Auth server using the code query parameter.
  • Exchange this code for a session, which we store in our chosen storage mechanism (in this case, cookies).
  • Finally, we redirect the user to the account page.

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// src/routes/auth/callback/+server.js
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import { redirect } from '@sveltejs/kit'
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export const GET = async ({ url, locals: { supabase } }) => {
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const code = url.searchParams.get('code')
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if (code) {
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await supabase.auth.exchangeCodeForSession(code)
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}
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redirect(303, '/account')
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}

Account page

After a user is signed in, they need to be able to edit their profile details and manage their account. Create a new src/routes/account/+page.svelte file with the content below.

src/routes/account/+page.svelte

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<!-- src/routes/account/+page.svelte -->
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<script lang="ts">
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import { enhance } from '$app/forms';
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import type { SubmitFunction } from '@sveltejs/kit';
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export let data
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export let form
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let { session, supabase, profile } = data
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$: ({ session, supabase, profile } = data)
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let profileForm: HTMLFormElement
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let loading = false
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let fullName: string = profile?.full_name ?? ''
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let username: string = profile?.username ?? ''
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let website: string = profile?.website ?? ''
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let avatarUrl: string = profile?.avatar_url ?? ''
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const handleSubmit: SubmitFunction = () => {
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loading = true
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return async () => {
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loading = false
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}
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}
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const handleSignOut: SubmitFunction = () => {
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loading = true
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return async ({ update }) => {
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loading = false
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update()
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}
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}
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</script>
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<div class="form-widget">
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<form
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class="form-widget"
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method="post"
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action="?/update"
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use:enhance={handleSubmit}
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bind:this={profileForm}
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>
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<div>
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<label for="email">Email</label>
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<input id="email" type="text" value={session.user.email} disabled />
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</div>
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<div>
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<label for="fullName">Full Name</label>
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<input id="fullName" name="fullName" type="text" value={form?.fullName ?? fullName} />
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</div>
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<div>
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<label for="username">Username</label>
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<input id="username" name="username" type="text" value={form?.username ?? username} />
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</div>
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<div>
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<label for="website">Website</label>
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<input id="website" name="website" type="url" value={form?.website ?? website} />
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</div>
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<div>
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<input
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type="submit"
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class="button block primary"
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value={loading ? 'Loading...' : 'Update'}
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disabled={loading}
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/>
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</div>
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</form>
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<form method="post" action="?/signout" use:enhance={handleSignOut}>
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<div>
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<button class="button block" disabled={loading}>Sign Out</button>
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</div>
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</form>
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</div>

Now create the associated src/routes/account/+page.server.ts file that will handle loading our data from the server through the load function and handle all our form actions through the actions object.


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import { fail, redirect } from '@sveltejs/kit'
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import type { Actions, PageServerLoad } from './$types'
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export const load: PageServerLoad = async ({ locals: { supabase, safeGetSession } }) => {
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const { session } = await safeGetSession()
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if (!session) {
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redirect(303, '/')
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}
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const { data: profile } = await supabase
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.from('profiles')
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.select(`username, full_name, website, avatar_url`)
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.eq('id', session.user.id)
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.single()
_62
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return { session, profile }
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}
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export const actions: Actions = {
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update: async ({ request, locals: { supabase, safeGetSession } }) => {
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const formData = await request.formData()
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const fullName = formData.get('fullName') as string
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const username = formData.get('username') as string
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const website = formData.get('website') as string
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const avatarUrl = formData.get('avatarUrl') as string
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const { session } = await safeGetSession()
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const { error } = await supabase.from('profiles').upsert({
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id: session?.user.id,
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full_name: fullName,
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username,
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website,
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avatar_url: avatarUrl,
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updated_at: new Date(),
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})
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if (error) {
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return fail(500, {
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fullName,
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username,
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website,
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avatarUrl,
_62
})
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}
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return {
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fullName,
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username,
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website,
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avatarUrl,
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}
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},
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signout: async ({ locals: { supabase, safeGetSession } }) => {
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const { session } = await safeGetSession()
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if (session) {
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await supabase.auth.signOut()
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redirect(303, '/')
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}
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},
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}

Launch!

Now that we have all the pages in place, run this in a terminal window:


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npm run dev

And then open the browser to localhost:5173 and you should see the completed app.

Supabase Svelte

Bonus: Profile photos

Every Supabase project is configured with Storage for managing large files like photos and videos.

Create an upload widget

Let's create an avatar for the user so that they can upload a profile photo. We can start by creating a new component called Avatar.svelte in the src/routes/account directory:

src/routes/account/Avatar.svelte

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<!-- src/routes/account/Avatar.svelte -->
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<script lang="ts">
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import type { SupabaseClient } from '@supabase/supabase-js'
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import { createEventDispatcher } from 'svelte'
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export let size = 10
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export let url: string
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export let supabase: SupabaseClient
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let avatarUrl: string | null = null
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let uploading = false
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let files: FileList
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const dispatch = createEventDispatcher()
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const downloadImage = async (path: string) => {
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try {
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const { data, error } = await supabase.storage.from('avatars').download(path)
_94
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if (error) {
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throw error
_94
}
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const url = URL.createObjectURL(data)
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avatarUrl = url
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} catch (error) {
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if (error instanceof Error) {
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console.log('Error downloading image: ', error.message)
_94
}
_94
}
_94
}
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const uploadAvatar = async () => {
_94
try {
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uploading = true
_94
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if (!files || files.length === 0) {
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throw new Error('You must select an image to upload.')
_94
}
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const file = files[0]
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const fileExt = file.name.split('.').pop()
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const filePath = `${Math.random()}.${fileExt}`
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const { error } = await supabase.storage.from('avatars').upload(filePath, file)
_94
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if (error) {
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throw error
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}
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url = filePath
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setTimeout(() => {
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dispatch('upload')
_94
}, 100)
_94
} catch (error) {
_94
if (error instanceof Error) {
_94
alert(error.message)
_94
}
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} finally {
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uploading = false
_94
}
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}
_94
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$: if (url) downloadImage(url)
_94
</script>
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<div>
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{#if avatarUrl}
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<img
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src={avatarUrl}
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alt={avatarUrl ? 'Avatar' : 'No image'}
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class="avatar image"
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style="height: {size}em; width: {size}em;"
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/>
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{:else}
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<div class="avatar no-image" style="height: {size}em; width: {size}em;" />
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{/if}
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<input type="hidden" name="avatarUrl" value={url} />
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<div style="width: {size}em;">
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<label class="button primary block" for="single">
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{uploading ? 'Uploading ...' : 'Upload'}
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</label>
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<input
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style="visibility: hidden; position:absolute;"
_94
type="file"
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id="single"
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accept="image/*"
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bind:files
_94
on:change={uploadAvatar}
_94
disabled={uploading}
_94
/>
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</div>
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</div>

Add the new widget

And then we can add the widget to the Account page:

src/routes/account/+page.svelte

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<!-- src/routes/account/+page.svelte -->
_27
<script lang="ts">
_27
// Import the new component
_27
import Avatar from './Avatar.svelte'
_27
</script>
_27
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<div class="form-widget">
_27
<form
_27
class="form-widget"
_27
method="post"
_27
action="?/update"
_27
use:enhance={handleSubmit}
_27
bind:this={profileForm}
_27
>
_27
<!-- Add to body -->
_27
<Avatar
_27
{supabase}
_27
bind:url={avatarUrl}
_27
size={10}
_27
on:upload={() => {
_27
profileForm.requestSubmit();
_27
}}
_27
/>
_27
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<!-- Other form elements -->
_27
</form>
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</div>

At this stage you have a fully functional application!