View hooks demo

Promotions.php

<?php

class Promotions
{
  public static function for(User $user)
  {
    return new static($user);
  }
  
  public function __construct(protected User $user)
  {
  }
  
  public function registerHooks()
  {
    if ($this->inCyberMondayWindow()) {
      View::hook('mail.receipt', 'promos', function() {
        return new HtmlString(Blade::render(<<<'BLADE'
          <x-mail-banner>
            Don't miss out on our <a href="#">Cyber Monday deals!</a>
          </x-mail-banner>
        BLADE
        ));
      });
    }
  }
  
  protected function inCyberMondayWindow()
  {
    $start = Date::parse('fourth monday of november')->toImmutable();
    $end = $start->addWeek();
    
    return now()->between($start, $end);
  }
}

receipt.blade.php

<x-email>
  <x-hook name="promos" />

  <p>Thank you for your purchase!</p>

  ...

</x-email>

ReceiptMail.php

<?php

class ReceiptMail extends Mailable
{
  public function __construct(
    public User $customer,
    public Collection $items
  ) {
  }
  
  public function build()
  {
    Promotions::for($this->customer)->registerHooks();
  }
  
  public function content(): Content
  {
    return new Content(view: 'mail.receipt');
  }
}