Add Short After Filter Syntax with one parameter

flight/core/Dispatcher.php

@@ -7,6 +7,7 @@ namespace flight\core;
 use Exception;
 use flight\Engine;
 use InvalidArgumentException;
+use ReflectionFunction;
 use TypeError;
 
 /**
@@ -208,6 +209,16 @@ class Dispatcher
             trigger_error($noticeMessage, E_USER_NOTICE);
         }
 
+        if ($type === self::FILTER_AFTER) {
+            $callbackInfo = new ReflectionFunction($callback);
+            $parametersNumber = $callbackInfo->getNumberOfParameters();
+
+            if ($parametersNumber === 1) {
+                /** @disregard &$params in after filters are deprecated. */
+                $callback = fn (array &$params, &$output) => $callback($output);
+            }
+        }
+
         $this->filters[$name][$type][] = $callback;
 
         return $this;

tests/DispatcherTest.php

@@ -37,9 +37,7 @@ class DispatcherTest extends TestCase
 
     public function testFunctionMapping(): void
     {
-        $this->dispatcher->set('map2', function (): string {
-            return 'hello';
-        });
+        $this->dispatcher->set('map2', fn (): string => 'hello');
 
         $this->assertSame('hello', $this->dispatcher->run('map2'));
     }
@@ -61,6 +59,9 @@ class DispatcherTest extends TestCase
             ->set('map-event', $customFunction)
             ->set('map-event-2', $anotherFunction);
 
+        $this->assertTrue($this->dispatcher->has('map-event'));
+        $this->assertTrue($this->dispatcher->has('map-event-2'));
+
         $this->dispatcher->clear();
 
         $this->assertFalse($this->dispatcher->has('map-event'));
@@ -76,6 +77,9 @@ class DispatcherTest extends TestCase
             ->set('map-event', $customFunction)
             ->set('map-event-2', $anotherFunction);
 
+        $this->assertTrue($this->dispatcher->has('map-event'));
+        $this->assertTrue($this->dispatcher->has('map-event-2'));
+
         $this->dispatcher->clear('map-event');
 
         $this->assertFalse($this->dispatcher->has('map-event'));
@@ -105,9 +109,7 @@ class DispatcherTest extends TestCase
 
     public function testBeforeAndAfter(): void
     {
-        $this->dispatcher->set('hello', function (string $name): string {
-            return "Hello, $name!";
-        });
+        $this->dispatcher->set('hello', fn (string $name): string => "Hello, $name!");
 
         $this->dispatcher
             ->hook('hello', Dispatcher::FILTER_BEFORE, function (array &$params): void {
@@ -124,6 +126,25 @@ class DispatcherTest extends TestCase
         $this->assertSame('Hello, Fred! Have a nice day!', $result);
     }
 
+    public function testBeforeAndAfterWithShortAfterFilterSyntax(): void
+    {
+        $this->dispatcher->set('hello', fn (string $name): string => "Hello, $name!");
+
+        $this->dispatcher
+            ->hook('hello', Dispatcher::FILTER_BEFORE, function (array &$params): void {
+                // Manipulate the parameter
+                $params[0] = 'Fred';
+            })
+            ->hook('hello', Dispatcher::FILTER_AFTER, function (string &$output): void {
+                // Manipulate the output
+                $output .= ' Have a nice day!';
+            });
+
+        $result = $this->dispatcher->run('hello', ['Bob']);
+
+        $this->assertSame('Hello, Fred! Have a nice day!', $result);
+    }
+
     public function testInvalidCallback(): void
     {
         $this->expectException(Exception::class);