Dependency Injection

Basics

Dependency Injection (DI) is a design pattern that allows you to inject automatically created services (or objects, etc.) without creating them manually. Viewi handles DI automatically by following these rules:

• Transient. Each component (class that is derived from BaseComponent) will be created each time you need it. Which means, every time you use your component as a tag (<MyComponent />) Viewi will create instance of that component for you.
• Singleton. Everything else will be considered as a Service class and will be resolved only once and will be reused every time you inject it.

All other DI rules are planned for future development. And you can always request it as feature on our github page so we will know how important it is for you.

How to inject

Easy:

• For components (based on BaseComponent) inject your services inside of __init function.
  
  

  <?php
  
  namespace Application\Components\Views\Demo\ServicesAndModels;
  
  use Application\Components\Services\Demo\CounterState;
  use Viewi\BaseComponent;
  
  class ServicesExample extends BaseComponent
  {
      public CounterState $counter;
  
      public function __init(CounterState $counterState)
      {
          $this->counter = $counterState;
      }    
  }
  

  
  
  
• For all other services you can inject your dependencies inside of __construct.
  
  

  <?php
  
  namespace Components\Services;
  
  use Viewi\Common\ClientRouter;
  use Viewi\Common\HttpClient;
  
  class AuthService
  {
      private HttpClient $http;
      private ClientRouter $router;
  
      public function __construct(HttpClient $httpClient, ClientRouter $clientRouter)
      {
          $this->http = $httpClient;
          $this->router = $clientRouter;
      }
  }