fix(user): persist detected timezones (#296)

## Summary
- store browser-detected IANA timezones on users during registration and
share the value to the frontend
- silently backfill missing timezones for authenticated users without
overwriting existing saved values
- add focused feature coverage for registration, shared props, and the
timezone backfill endpoint

## Testing
- php artisan test --compact tests/Feature/Auth/RegistrationTest.php
tests/Feature/InertiaSharedDataTest.php
tests/Feature/Settings/TimezoneTest.php
- npm test -- resources/js/utils/currency.test.ts

app/Actions/Fortify/CreateNewUser.php

@@ -28,6 +28,7 @@ class CreateNewUser implements CreatesNewUsers
                 Rule::unique(User::class),
             ],
             'password' => $this->passwordRules(),
+            'timezone' => ['nullable', 'string', 'timezone'],
         ])->validate();
 
         $user = User::create([
@@ -35,6 +36,7 @@ class CreateNewUser implements CreatesNewUsers
             'email' => $input['email'],
             'password' => $input['password'],
             'locale' => $this->detectLocaleFromRequest(),
+            'timezone' => $input['timezone'] ?? null,
         ]);
 
         if (! config('mail.email_verification_enabled')) {

app/Http/Controllers/Settings/TimezoneController.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Http\Controllers\Settings;
+
+use App\Http\Controllers\Controller;
+use App\Http\Requests\Settings\UpdateTimezoneRequest;
+use Illuminate\Http\Response;
+
+class TimezoneController extends Controller
+{
+    public function update(UpdateTimezoneRequest $request): Response
+    {
+        $user = $request->user();
+
+        if ($user->timezone === null) {
+            $user->update(['timezone' => $request->validated('timezone')]);
+        }
+
+        return response()->noContent();
+    }
+}

app/Http/Requests/Settings/UpdateTimezoneRequest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Http\Requests\Settings;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class UpdateTimezoneRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    public function rules(): array
+    {
+        return [
+            'timezone' => ['required', 'string', 'timezone'],
+        ];
+    }
+}

app/Models/User.php

@@ -37,6 +37,7 @@ class User extends Authenticatable implements HasLocalePreference, MustVerifyEma
         'paywall_seen_at',
         'currency_code',
         'locale',
+        'timezone',
     ];
 
     /**

database/migrations/2026_04_16_092644_add_timezone_to_users_table.php

@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->string('timezone')->nullable()->after('locale');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->dropColumn('timezone');
+        });
+    }
+};

resources/js/app.tsx

@@ -2,6 +2,7 @@ import '../css/app.css';
 
 import { createInertiaApp, router } from '@inertiajs/react';
 import * as Sentry from '@sentry/react';
+import axios from 'axios';
 import { resolvePageComponent } from 'laravel-vite-plugin/inertia-helpers';
 import {
     CircleCheckIcon,
@@ -37,6 +38,7 @@ initializeTheme();
 initializeChartColorScheme();
 
 const appName = import.meta.env.VITE_APP_NAME || 'Laravel';
+let hasAttemptedTimezoneBackfill = false;
 
 // Determine progress bar color based on current theme
 const getProgressBarColor = () => {
@@ -65,6 +67,31 @@ createInertiaApp({
         const hasEncryptedTransactions =
             (initialPageProps?.hasEncryptedTransactions as boolean) ?? false;
 
+        const syncUserTimezone = async (pageProps?: Partial<SharedData>) => {
+            const user = pageProps?.auth?.user ?? null;
+            const detectedTimezone =
+                Intl.DateTimeFormat().resolvedOptions().timeZone;
+
+            if (
+                hasAttemptedTimezoneBackfill ||
+                !user ||
+                user.timezone ||
+                !detectedTimezone
+            ) {
+                return;
+            }
+
+            hasAttemptedTimezoneBackfill = true;
+
+            try {
+                await axios.patch('/settings/timezone', {
+                    timezone: detectedTimezone,
+                });
+            } catch {
+                hasAttemptedTimezoneBackfill = false;
+            }
+        };
+
         // Initialize translations from server-rendered page data
         setTranslations(
             (initialPageProps?.translations as Record<string, string>) ?? {},
@@ -72,12 +99,16 @@ createInertiaApp({
 
         // Keep translations in sync on every Inertia navigation
         router.on('navigate', (event) => {
-            const pageProps = event.detail.page.props as SharedData;
+            const pageProps = event.detail.page.props as unknown as SharedData;
             setTranslations(
                 (pageProps?.translations as Record<string, string>) ?? {},
             );
+
+            void syncUserTimezone(pageProps);
         });
 
+        void syncUserTimezone(initialPageProps);
+
         root.render(
             <StrictMode>
                 <EncryptionKeyProvider

resources/js/pages/auth/register.tsx

@@ -18,6 +18,11 @@ interface RegisterProps {
 }
 
 export default function Register({ hideAuthButtons = false }: RegisterProps) {
+    const detectedTimezone =
+        typeof window !== 'undefined'
+            ? Intl.DateTimeFormat().resolvedOptions().timeZone || ''
+            : '';
+
     useEffect(() => {
         if (hideAuthButtons) {
             router.visit(login());
@@ -48,6 +53,12 @@ export default function Register({ hideAuthButtons = false }: RegisterProps) {
             >
                 {({ processing, errors }) => (
                     <>
+                        <input
+                            type="hidden"
+                            name="timezone"
+                            value={detectedTimezone}
+                        />
+
                         <div className="grid gap-6">
                             <div className="grid gap-2">
                                 <Label htmlFor="name">{__('Name')}</Label>

resources/js/types/index.d.ts

@@ -84,6 +84,7 @@ export interface User {
     email: string;
     currency_code: CurrencyCode;
     locale: string | null;
+    timezone: string | null;
     avatar?: string;
     email_verified_at: string | null;
     two_factor_enabled?: boolean;

routes/settings.php

@@ -11,6 +11,7 @@ use App\Http\Controllers\Settings\NetWorthChartLoanPreferenceController;
 use App\Http\Controllers\Settings\NetWorthChartRealEstatePreferenceController;
 use App\Http\Controllers\Settings\PasswordController;
 use App\Http\Controllers\Settings\ProfileController;
+use App\Http\Controllers\Settings\TimezoneController;
 use App\Http\Controllers\Settings\TwoFactorAuthenticationController;
 use App\Http\Controllers\SubscriptionController;
 use Illuminate\Support\Facades\Route;
@@ -21,6 +22,7 @@ Route::middleware('auth')->group(function () {
 
     Route::get('settings/account', [ProfileController::class, 'account'])->name('account.edit');
     Route::patch('settings/profile', [ProfileController::class, 'update'])->name('profile.update');
+    Route::patch('settings/timezone', [TimezoneController::class, 'update'])->name('timezone.update');
     Route::delete('settings/profile', [ProfileController::class, 'destroy'])
         ->middleware('block-demo')
         ->name('profile.destroy');

tests/Feature/Auth/RegistrationTest.php

@@ -6,7 +6,7 @@ use Illuminate\Support\Facades\Notification;
 use Illuminate\Support\Facades\Queue;
 
 test('registration screen can be rendered', function () {
-    $response = $this->get(route('register'));
+    $response = $this->withoutVite()->get(route('register'));
 
     $response->assertSuccessful();
 });
@@ -25,6 +25,37 @@ test('new users can register', function () {
     $response->assertRedirect(route('onboarding', absolute: false));
 });
 
+test('new users store their detected timezone on registration', function () {
+    Queue::fake();
+
+    $this->post(route('register.store'), [
+        'name' => 'Test User',
+        'email' => 'test@example.com',
+        'password' => 'password',
+        'password_confirmation' => 'password',
+        'timezone' => 'America/New_York',
+    ]);
+
+    $user = User::where('email', 'test@example.com')->first();
+
+    expect($user->timezone)->toBe('America/New_York');
+});
+
+test('new users can register without a timezone', function () {
+    Queue::fake();
+
+    $this->post(route('register.store'), [
+        'name' => 'Test User',
+        'email' => 'test@example.com',
+        'password' => 'password',
+        'password_confirmation' => 'password',
+    ]);
+
+    $user = User::where('email', 'test@example.com')->first();
+
+    expect($user->timezone)->toBeNull();
+});
+
 test('new users receive a verification email on registration', function () {
     Notification::fake();
 

tests/Feature/InertiaSharedDataTest.php

@@ -6,7 +6,7 @@ use Inertia\Testing\AssertableInertia as Assert;
 use function Pest\Laravel\actingAs;
 
 test('guests receive null auth user in shared props', function () {
-    $response = $this->get(route('home'));
+    $response = $this->withoutVite()->get(route('home'));
 
     $response->assertInertia(fn (Assert $page) => $page
         ->where('auth.user', null)
@@ -14,18 +14,19 @@ test('guests receive null auth user in shared props', function () {
 });
 
 test('authenticated users receive auth user in shared props', function () {
-    $user = User::factory()->create();
+    $user = User::factory()->create(['timezone' => 'Europe/Madrid']);
 
-    $response = actingAs($user)->get(route('home'));
+    $response = actingAs($user)->withoutVite()->get(route('home'));
 
     $response->assertInertia(fn (Assert $page) => $page
         ->where('auth.user.id', $user->id)
         ->where('auth.user.email', $user->email)
+        ->where('auth.user.timezone', 'Europe/Madrid')
     );
 });
 
 test('all pages receive app url in shared props', function () {
-    $response = $this->get(route('home'));
+    $response = $this->withoutVite()->get(route('home'));
 
     $response->assertInertia(fn (Assert $page) => $page
         ->where('appUrl', config('app.url'))
@@ -33,7 +34,7 @@ test('all pages receive app url in shared props', function () {
 });
 
 test('shared currency options split profile and account currencies', function () {
-    $response = $this->get(route('home'));
+    $response = $this->withoutVite()->get(route('home'));
 
     $response->assertInertia(fn (Assert $page) => $page
         ->where('currencies.profile.0.code', 'USD')

tests/Feature/Settings/TimezoneTest.php

@@ -0,0 +1,46 @@
+<?php
+
+use App\Models\User;
+
+test('timezone can be backfilled for authenticated users without one', function () {
+    $user = User::factory()->create(['timezone' => null]);
+
+    $response = $this->actingAs($user)->patchJson(route('timezone.update'), [
+        'timezone' => 'Europe/Madrid',
+    ]);
+
+    $response->assertNoContent();
+
+    expect($user->refresh()->timezone)->toBe('Europe/Madrid');
+});
+
+test('timezone backfill does not overwrite an existing timezone', function () {
+    $user = User::factory()->create(['timezone' => 'America/New_York']);
+
+    $response = $this->actingAs($user)->patchJson(route('timezone.update'), [
+        'timezone' => 'Europe/Madrid',
+    ]);
+
+    $response->assertNoContent();
+
+    expect($user->refresh()->timezone)->toBe('America/New_York');
+});
+
+test('timezone backfill rejects invalid timezones', function () {
+    $user = User::factory()->create(['timezone' => null]);
+
+    $response = $this->actingAs($user)->patchJson(route('timezone.update'), [
+        'timezone' => 'Mars/Olympus_Mons',
+    ]);
+
+    $response->assertJsonValidationErrors(['timezone']);
+    expect($user->refresh()->timezone)->toBeNull();
+});
+
+test('timezone backfill requires authentication', function () {
+    $response = $this->patch(route('timezone.update'), [
+        'timezone' => 'Europe/Madrid',
+    ]);
+
+    $response->assertRedirect(route('login'));
+});