refactor EventDispatcher

src/core/EventDispatcher.php

@@ -6,51 +6,44 @@ namespace flight\core;
 
 class EventDispatcher
 {
-    /** @var self|null Singleton instance of the EventDispatcher */
+    /** Singleton instance of the EventDispatcher */
     private static ?self $instance = null;
 
-    /** @var array<string, array<int, callable>> */
+    /** @var array<string, array<int, callable(): mixed>> */
     protected array $listeners = [];
 
-    /**
+    /** Singleton instance of the EventDispatcher. */
-     * Singleton instance of the EventDispatcher.
-     *
-     * @return self
-     */
     public static function getInstance(): self
     {
-        if (self::$instance === null) {
+        if (!self::$instance) {
             self::$instance = new self();
         }
+
         return self::$instance;
     }
 
     /**
      * Register a callback for an event.
-     *
      * @param string $event Event name
-     * @param callable $callback Callback function
+     * @param callable(): mixed $callback Callback function
      */
     public function on(string $event, callable $callback): void
     {
-        if (isset($this->listeners[$event]) === false) {
+        $this->listeners[$event] ??= [];
-            $this->listeners[$event] = [];
-        }
         $this->listeners[$event][] = $callback;
     }
 
     /**
      * Trigger an event with optional arguments.
-     *
      * @param string $event Event name
      * @param mixed ...$args Arguments to pass to the callbacks
-     *
      * @return mixed
      */
     public function trigger(string $event, ...$args)
     {
         $result = null;
-        if (isset($this->listeners[$event]) === true) {
+
+        if (isset($this->listeners[$event])) {
             foreach ($this->listeners[$event] as $callback) {
                 $result = call_user_func_array($callback, $args);
 
@@ -60,27 +53,24 @@ class EventDispatcher
                 }
             }
         }
+
         return $result;
     }
 
     /**
      * Check if an event has any registered listeners.
-     *
      * @param string $event Event name
-     *
      * @return bool True if the event has listeners, false otherwise
      */
     public function hasListeners(string $event): bool
     {
-        return isset($this->listeners[$event]) === true && count($this->listeners[$event]) > 0;
+        return isset($this->listeners[$event]) && count($this->listeners[$event]) > 0;
     }
 
     /**
      * Get all listeners registered for a specific event.
-     *
      * @param string $event Event name
-     *
+     * @return array<int, callable(): mixed> Array of callbacks registered for the event
-     * @return array<int, callable> Array of callbacks registered for the event
      */
     public function getListeners(string $event): array
     {
@@ -89,7 +79,6 @@ class EventDispatcher
 
     /**
      * Get a list of all events that have registered listeners.
-     *
      * @return array<int, string> Array of event names
      */
     public function getAllRegisteredEvents(): array
@@ -99,41 +88,31 @@ class EventDispatcher
 
     /**
      * Remove a specific listener for an event.
-     *
      * @param string   $event    the event name
-     * @param callable $callback the exact callback to remove
+     * @param callable(): mixed $callback the exact callback to remove
-     *
-     * @return void
      */
     public function removeListener(string $event, callable $callback): void
     {
-        if (isset($this->listeners[$event]) === true && count($this->listeners[$event]) > 0) {
+        if ($this->hasListeners($event)) {
-            $this->listeners[$event] = array_filter($this->listeners[$event], function ($listener) use ($callback) {
+            $this->listeners[$event] = array_filter(
-                return $listener !== $callback;
+                $this->listeners[$event],
-            });
+                static fn(callable $listener): bool => $listener !== $callback,
+            );
+
             $this->listeners[$event] = array_values($this->listeners[$event]); // Re-index the array
         }
     }
 
     /**
      * Remove all listeners for a specific event.
-     *
      * @param string $event the event name
-     *
-     * @return void
      */
     public function removeAllListeners(string $event): void
     {
-        if (isset($this->listeners[$event]) === true) {
         unset($this->listeners[$event]);
     }
-    }
 
-    /**
+    /** Remove the current singleton instance of the EventDispatcher. */
-     * Remove the current singleton instance of the EventDispatcher.
-     *
-     * @return void
-     */
     public static function resetInstance(): void
     {
         self::$instance = null;