How to share a variable across all views?

I usually use View Composers so it's more clear and readable.

For example If I want to share a variable with the main navbar to all of my views I follow the below rules:

1. Create new service provider

You can create a service provider with artisan cli:

php artisan make:provider ViewComposerServiceProvider

In the ViewComposerServiceProvider file create composeNavigation method in which has the blade template main.nav-menu that represents the navmenu with shared variables.

The ViewComposerServiceProvider looks like:

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;

class ViewComposerServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap the application services.
     *
     * @return void
     */
    public function boot()
    {
        $this->composeNavigation();
    }

    /**
     * Register the application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }

    private function composeNavigation()
    {
        view()->composer('main.nav-menu', 'App\Http\ViewComposers\NavComposer');
    }
}

2. Create Composer

As you saw in the file above we have App\Http\ViewComposers\NavComposer.php so let's create that file. Create the folder ViewComposers in the App\Http and then inside create NavComposer.php file.

The NavComposer.php file:

<?php

namespace App\Http\ViewComposers;

use App\Repositories\NavMenuRepository;
use Illuminate\View\View;

class NavComposer
{
    protected $menu;

    public function __construct(NavMenuRepository $menu)
    {
        $this->menu = $menu;
    }

    public function compose(View $view)
    {
        $thing= $this->menu->thing();
        $somethingElse = $this->menu->somethingElseForMyDatabase();

        $view->with(compact('thing', 'somethingElse'));
    }
}

3. Create repository

As you saw above in the NavComposer.php file we have repository. Usually, I create a repository in the App directory, so create Repositories directory in the App and then, create inside NavMenuRepository.php file.

This file is the heart of that design pattern. In that file we have to take the value of our variables that we want to share with all of our views.

Take a look at the file bellow:

<?php

namespace App\Repositories;

use App\Thing;
use DB;

class NavMenuRepository
{

    public function thing()
    {
        $getVarForShareWithAllViews = Thing::where('name','something')->firstOrFail();
        return $getVarForShareWithAllViews;
    }

    public function somethingElseForMyDatabase()
    {
        $getSomethingToMyViews = DB::table('table')->select('name', 'something')->get();

        return $getSomethingToMyViews;
    }

}

For people with small project:

Firstly, The accepted answer is awesome!

For Laravel 5.2 users:

Just use the new blade directive @inject within your views like this

@inject('shared','App\Utilities\SharedWithView')

then you can use it: {{ $shared->functionName() }}

And SharedWithView is a simple class like this one:

namespace App\Utilities;

use App\Repositories\SomeRepositoryLikeArticlesRepository;

class SharedWithView {

    public function functionName() {
        $properNameHere = new SomeRepositoryLikeArticlesRepository();

        return $properNameHere->forEaxmpleGetMostViewedArticles( 10 );
    }

}