New when() helper. (#52665)

* feat(blade): New @when directive.

* StyleCI

* fix: move to compilesConditionals + remove default expression

* fix: styleCI

* fix: when() returns the value, rather than echoing it.

* fix: Remove @throws tags

* fix: styleCI

* fix: escaping on by default

* fix: remove blade directive and adds tests for when helper

* StyleCI

* remove default, add more tests.

* Remove return type

* StyleCI

* Update helpers.php

* move function

---------

Co-authored-by: Taylor Otwell <taylor@laravel.com>

Author: danmatthews

src/Illuminate/Collections/helpers.php

@@ -236,3 +236,21 @@ function value($value, ...$args)
         return $value instanceof Closure ? $value(...$args) : $value;
     }
 }
+
+if (! function_exists('when')) {
+    /**
+     * Output a value if the given condition is true.
+     *
+     * @param  mixed  $condition
+     * @param  \Closure|mixed  $output
+     * @return mixed
+     */
+    function when($condition, $output)
+    {
+        if ($condition) {
+            return value($output);
+        }
+
+        return null;
+    }
+}

tests/Support/SupportHelpersTest.php

@@ -100,6 +100,20 @@ public function testClassBasename()
         $this->assertSame('..', class_basename('\Foo\Bar\Baz\\..\\'));
     }
 
+    public function testWhen()
+    {
+        $this->assertEquals('Hello', when(true, 'Hello'));
+        $this->assertEquals(null, when(false, 'Hello'));
+        $this->assertEquals('There', when(1 === 1, 'There')); // strict types
+        $this->assertEquals('There', when(1 == '1', 'There')); // loose types
+        $this->assertEquals(null, when(1 == 2, 'There'));
+        $this->assertEquals(null, when('1', fn () => null));
+        $this->assertEquals(null, when(0, fn () => null));
+        $this->assertEquals('True', when([1, 2, 3, 4], 'True')); // Array
+        $this->assertEquals(null, when([], 'True')); // Empty Array = Falsy
+        $this->assertEquals('True', when(new StdClass, fn () => 'True')); // Object
+    }
+
     public function testFilled()
     {
         $this->assertFalse(filled(null));