Problems creating a ComposerServiceProvider in Laravel 5.4 - laravel

Question

Im working on a Laravel 5 app and im trying to set up a ComposerServiceProvider to pass data to a couple of views (im trying now to add it to the layout/app.blade.php).
I did this following the documentation but the data im trying to add is still undefined..
In my config/app.php I added to the providers:
App\Providers\ComposerServiceProvider::class,
On ComposerServiceProvider.php
boot method:
View::composer(['layouts.app'], 'App\ViewComposers\LayoutAppComposer');
On the new created LayoutAppComposer.php
compose(View $view) method:
$metaTitle = 'MetaTitle';
$view->with('metaTitle', $metaTitle)
But When i access the url I still get:
Undefined variable: metaTitle (View: .../resources/views/layouts/app.blade.php)
Am I missing something here??
ServiceProvider
namespace App\Providers;
use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\View;
class ComposerServiceProvider extends ServiceProvider
{
/**
* Bootstrap the application services.
*
* #return void
*/
public function boot()
{
View::composer(['layouts.app'], 'App\ViewComposers\LayoutAppComposer');
}
/**
* Register the application services.
*
* #return void
*/
public function register()
{
}
}
LayoutAppComposer
<?php
namespace App\ViewComposers;
use Illuminate\Support\Facades\Session;
use Illuminate\View\View;
class LayoutAppComposer {
protected $metaTitle;
public function __construct($metaTitle)
{
$this->metaTitle = $metaTitle;
}
/**
* Bind data to the view.
*
* #param View $view
* #return void
*/
public function compose(View $view) {
$this->metaTitle = 'MetaTitle';
$view->with('metaTitle', $this->metaTitle);
}
}

Answer 1

Try changing:
$metaTitle = 'MetaTitle';
$view->with('metaTitle', $metaTitle)
to
$this->metaTitle = 'metaTitle';
$view->with('metaTitle', $this->metaTitle)
setup $this->metaTitle as a protected class member and assign it in the composer constructor. it may be that $metaTitle is getting garbage collected before you use it since this being resolved at the service provider level.
Since you're registering the composer with your app layout, instead you may need to use the wildcard character in place of app.layout like such:
View::composer('*', function ($view) {
//
});
To resolve $metaTile for the View Composer, try binding in your AppServiceProvider:
$this->app->bind('metaTitle', 'the string i want displayed across all views');