Shared data

Shared props are added to every page, typically the authenticated user, flash messages or application settings.

In the configuration

// config/web.php
'components' => [
    'inertia' => [
        'shared' => [
            'appName' => 'My Application',
            'auth.user' => fn () => Yii::$app->user->identity?->toArray(['id', 'name', 'email']),
            'locale' => fn () => Yii::$app->language,
        ],
    ],
],

At runtime

Share props from a bootstrap class, a base controller or a filter:

use Crenspire\Yii2Inertia\Inertia;

Inertia::share('locale', Yii::$app->language);

Inertia::share([
    'auth.can' => fn () => [
        'manageUsers' => Yii::$app->user->can('manageUsers'),
    ],
]);

A bootstrap class is a convenient place for application-wide props:

namespace app\components;

use Crenspire\Yii2Inertia\Inertia;
use Yii;
use yii\base\BootstrapInterface;

class InertiaBootstrap implements BootstrapInterface
{
    public function bootstrap($app): void
    {
        Inertia::share([
            'auth.user' => static fn () => Yii::$app->user->identity?->toArray(['id', 'name', 'email']),
        ]);
    }
}

// config/web.php
'bootstrap' => ['log', \app\components\InertiaBootstrap::class],

Use closures for anything that depends on the request or the user: they are evaluated when the page is rendered, not when the prop is shared.

Props passed to Inertia::render() override shared props with the same key.

Reading and clearing shared props

Inertia::getShared();                      // all shared props (unevaluated)
Inertia::getShared('auth.user');           // one prop, dot notation supported
Inertia::getShared('missing', 'default');  // with a default value
Inertia::flushShared();                    // remove all shared props

The errors prop

Every page has an errors prop containing the validation errors flashed with Inertia::withErrors(), or an empty object. It is always included, even in partial reloads.

Shared props on the client

The page object lists the shared prop keys in sharedProps, which lets the client carry them over during client-side visits. Disable it with exposeSharedPropKeys.

Shared props follow the same rules as page props: they are skipped by partial reloads that do not request them. Wrap a shared prop in Inertia::always() when it must be included in every response:

Inertia::share('notifications', Inertia::always(fn () => Notification::unreadCount()));

Shared props that rarely change can be sent once and remembered by the client, see once props:

Inertia::shareOnce('countries', fn () => Country::find()->select(['code', 'name'])->asArray()->all());