Explain Laravel's service container and dependency injection

Imagine we have two classes:

1. A Superhero (a toy).
2. A Cape (an extra part the superhero needs to fly).

Step-by-Step Breakdown

1. Superhero Class (Needs a Cape):

   class Superhero
   {
       protected $cape;
   
       // Superhero needs a Cape to fly
       public function __construct(Cape $cape)
       {
           $this->cape = $cape;
       }
   
       public function fly()
       {
           return "Flying with a " . $this->cape->type();
       }
   }
   

2. Cape Class (The Extra Part):

   class Cape
   {
       public function type()
       {
           return 'red cape!';
       }
   }

Bind Superhero and Cape in the service provider

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;

class ToyStoreServiceProvider extends ServiceProvider
{
    /**
     * Register services.
     *
     * @return void
     */
    public function register()
    {
        // Binding Cape class
        $this->app->bind(Cape::class, function () {
            return new Cape();
        });

        // Binding Superhero class, which depends on Cape
        $this->app->bind(Superhero::class, function ($app) {
            return new Superhero($app->make(Cape::class));
        });
    }

    /**
     * Bootstrap services.
     *
     * @return void
     */
    public function boot()
    {
        // Any bootstrapping code can go here
    }
}


Resolving the Classes

Now, when you resolve the Superhero, Laravel will automatically create the Cape instance since you’re creating it directly in the closure of the Superhero binding:

$superhero = app(Superhero::class);
echo $superhero->fly();  // Output: "Flying with a red cape!"

Thank you