Livewire allows you to lazy load components that would otherwise slow down the initial page load.
Livewire provides two ways to delay component loading:
lazy): Components load when they become visible in the viewport (when the user scrolls to them)defer): Components load immediately after the initial page load is completeBoth approaches prevent slow components from blocking your initial page render, but differ in when the component actually loads.
For example, imagine you have a revenue component which contains a slow database query in mount():
<?php // resources/views/components/⚡revenue.blade.php
use Livewire\Component;
use App\Models\Transaction;
new class extends Component {
public $amount;
public function mount()
{
// Slow database query...
$this->amount = Transaction::monthToDate()->sum('amount');
}
};
?>
<div>
Revenue this month: {{ $amount }}
</div>Without lazy loading, this component would delay the loading of the entire page and make your entire application feel slow.
To enable lazy loading, you can pass the lazy parameter into the component:
<livewire:revenue lazy />Now, instead of loading the component right away, Livewire will skip this component, loading the page without it. Then, when the component is visible in the viewport, Livewire will make a network request to fully load this component on the page.
[!info] Lazy and deferred requests are isolated by default Unlike other network requests in Livewire, lazy and deferred component updates are isolated from each other when sent to the server. This keeps loading fast by loading each component in parallel. Read more about bundling components →
By default, Livewire will insert an empty <div></div> for your component before it is fully loaded. As the component will initially be invisible to users, it can be jarring when the component suddenly appears on the page.
To signal to your users that the component is being loaded, you can render placeholder HTML like loading spinners and skeleton placeholders.
For single-file and multi-file components, you can use the @placeholder directive directly in your view to specify placeholder content:
<?php // resources/views/components/⚡revenue.blade.php
use Livewire\Component;
use App\Models\Transaction;
new class extends Component {
public $amount;
public function mount()
{
// Slow database query...
$this->amount = Transaction::monthToDate()->sum('amount');
}
};
?>
@placeholder
<div>
<!-- Loading spinner... -->
<svg>...</svg>
</div>
@endplaceholder
<div>
Revenue this month: {{ $amount }}
</div>The content inside @placeholder and @endplaceholder will be displayed while the component is loading, then replaced with the actual component content once loaded.
[!tip] Placeholder directive for view-based components only The@placeholderdirective is only available for view-based components (single-file and multi-file components). For class-based components, use theplaceholder()method instead.
[!warning] The placeholder and the component must share the same element type For instance, if your placeholder's root element type is a 'div,' your component must also use a 'div' element.
For class-based components, or if you prefer programmatic control, you can define a placeholder() method that returns HTML:
<?php
namespace App\Livewire;
use Livewire\Component;
use App\Models\Transaction;
class Revenue extends Component
{
public $amount;
public function mount()
{
// Slow database query...
$this->amount = Transaction::monthToDate()->sum('amount');
}
public function placeholder()
{
return <<<'HTML'
<div>
<!-- Loading spinner... -->
<svg>...</svg>
</div>
HTML;
}
public function render()
{
return view('livewire.revenue');
}
}For more complex loaders (such as skeletons) you can return a view from the placeholder() method:
public function placeholder(array $params = [])
{
return view('livewire.placeholders.skeleton', $params);
}Any parameters from the component being lazy loaded will be available as an $params argument passed to the placeholder() method.
By default, lazy-loaded components aren't fully loaded until they enter the browser's viewport, for example when a user scrolls to one.
If you'd rather load components immediately after the page is loaded, without waiting for them to enter the viewport, you can use the defer parameter instead:
<livewire:revenue defer />Now this component will load as soon as the page is ready without waiting for it to be visible in the viewport.
You can also use the #[Defer] attribute to make a component defer-loaded by default:
<?php
namespace App\Livewire;
use Livewire\Component;
use Livewire\Attributes\Defer;
#[Defer]
class Revenue extends Component
{
// ...
}[!tip] Legacy on-load syntax You can also uselazy="on-load"which behaves the same asdefer. Thedeferparameter is recommended for new code.
In general, you can treat lazy components the same as normal components, since you can still pass data into them from outside.
For example, here's a scenario where you might pass a time interval into the Revenue component from a parent component:
<input type="date" wire:model="start">
<input type="date" wire:model="end">
<livewire:revenue lazy :$start :$end />You can accept this data in mount() just like any other component:
<?php // resources/views/components/⚡revenue.blade.php
use Livewire\Component;
use App\Models\Transaction;
new class extends Component {
public $amount;
public function mount($start, $end)
{
// Expensive database query...
$this->amount = Transactions::between($start, $end)->sum('amount');
}
};
?>
@placeholder
<div>
<!-- Loading spinner... -->
<svg>...</svg>
</div>
@endplaceholder
<div>
Revenue this month: {{ $amount }}
</div>However, unlike a normal component load, a lazy component has to serialize or "dehydrate" any passed-in properties and temporarily store them on the client-side until the component is fully loaded.
For example, you might want to pass in an Eloquent model to the revenue component like so:
<livewire:revenue lazy :$user />In a normal component, the actual PHP in-memory $user model would be passed into the mount() method of revenue. However, because we won't run mount() until the next network request, Livewire will internally serialize $user to JSON and then re-query it from the database before the next request is handled.
Typically, this serialization should not cause any behavioral differences in your application.
If you want to enforce that all usages of a component will be lazy-loaded or deferred, you can add the #[Lazy] or #[Defer] attribute above the component class:
<?php
namespace App\Livewire;
use Livewire\Component;
use Livewire\Attributes\Lazy;
#[Lazy]
class Revenue extends Component
{
// ...
}Or for deferred loading:
<?php
namespace App\Livewire;
use Livewire\Component;
use Livewire\Attributes\Defer;
#[Defer]
class Revenue extends Component
{
// ...
}You can override these defaults when rendering a component:
{{-- Disable lazy loading --}}
<livewire:revenue :lazy="false" />
{{-- Disable deferred loading --}}
<livewire:revenue :defer="false" />By default, if there are multiple lazy-loaded components on the page, each component will make an independent network request in parallel. This is often desirable for performance as each component loads independently.
However, if you have many lazy components on a page, you may want to bundle them into a single network request to reduce server overhead.
You can enable bundling using the bundle: true parameter:
<?php
namespace App\Livewire;
use Livewire\Component;
use Livewire\Attributes\Lazy;
#[Lazy(bundle: true)]
class Revenue extends Component
{
// ...
}Now, if there are ten Revenue components on the same page, when the page loads, all ten updates will be bundled and sent to the server as a single network request.
You can also enable bundling inline when rendering a component using the bundle modifier:
<livewire:revenue lazy.bundle />This also works with deferred components:
<livewire:revenue defer.bundle />Or using the attribute:
<?php
namespace App\Livewire;
use Livewire\Component;
use Livewire\Attributes\Defer;
#[Defer(bundle: true)]
class Revenue extends Component
{
// ...
}Use bundling when:
Don't use bundling when:
[!tip] Legacy isolate syntax You can also useisolate: falsewhich behaves the same asbundle: true. Thebundleparameter is recommended for new code as it's more explicit about the intent.
You can lazy load or defer full-page Livewire components using route methods.
Use ->lazy() to load the component when it enters the viewport:
Route::livewire('/dashboard', 'pages::dashboard')->lazy();Use ->defer() to load the component immediately after the page loads:
Route::livewire('/dashboard', 'pages::dashboard')->defer();If a component is lazy or deferred by default (via the #[Lazy] or #[Defer] attribute), you can opt-out using enabled: false:
Route::livewire('/dashboard', 'pages::dashboard')->lazy(enabled: false);
Route::livewire('/dashboard', 'pages::dashboard')->defer(enabled: false);If you want to set a default placeholder view for all your components you can do so by referencing the view in the /config/livewire.php config file:
'component_placeholder' => 'livewire.placeholder',Now, when a component is lazy-loaded and no placeholder() is defined, Livewire will use the configured Blade view (livewire.placeholder in this case.)
When unit testing a lazy component, or a page with nested lazy components, you may want to disable the "lazy" behavior so that you can assert the final rendered behavior. Otherwise, those components would be rendered as their placeholders during your tests.
You can easily disable lazy loading using the Livewire::withoutLazyLoading() testing helper like so:
<?php
namespace Tests\Feature\Livewire;
use App\Livewire\Dashboard;
use Livewire\Livewire;
use Tests\TestCase;
class DashboardTest extends TestCase
{
public function test_renders_successfully()
{
Livewire::withoutLazyLoading() // [tl! highlight]
->test(Dashboard::class)
->assertSee(...);
}
}Now, when the dashboard component is rendered for this test, it will skip rendering the placeholder() and instead render the full component as if lazy loading wasn't applied at all.