[8.x] Add Str::headline() (#39174)

* Add `Str::studlyWords()`

* Rename method to `headline` and alter logic to properly handle title test cases

* Add more assertions

Co-authored-by: Steve Bauman <6421846+stevebauman@users.noreply.github.com>

src/Illuminate/Support/Str.php

@@ -679,6 +679,27 @@ public static function title($value)
         return mb_convert_case($value, MB_CASE_TITLE, 'UTF-8');
     }
 
+    /**
+     * Convert the given string to title case for each word.
+     *
+     * @param  string  $value
+     * @return string
+     */
+    public static function headline($value)
+    {
+        $parts = explode('_', static::replace(' ', '_', $value));
+
+        if (count($parts) > 1) {
+            $parts = array_map([static::class, 'title'], $parts);
+        }
+
+        $studly = static::studly(implode($parts));
+
+        $words = preg_split('/(?=[A-Z])/', $studly, -1, PREG_SPLIT_NO_EMPTY);
+
+        return implode(' ', $words);
+    }
+
     /**
      * Get the singular form of an English word.
      *

src/Illuminate/Support/Stringable.php

@@ -596,6 +596,16 @@ public function title()
         return new static(Str::title($this->value));
     }
 
+    /**
+     * Convert the given string to title case for each word.
+     *
+     * @return static
+     */
+    public function headline()
+    {
+        return new static(Str::headline($this->value));
+    }
+
     /**
      * Get the singular form of an English word.
      *

tests/Support/SupportStrTest.php

@@ -35,6 +35,25 @@ public function testStringTitle()
         $this->assertSame('Jefferson Costella', Str::title('jefFErson coSTella'));
     }
 
+    public function testStringHeadline()
+    {
+        $this->assertSame('Jefferson Costella', Str::headline('jefferson costella'));
+        $this->assertSame('Jefferson Costella', Str::headline('jefFErson coSTella'));
+        $this->assertSame('Jefferson Costella Uses Laravel', Str::headline('jefferson_costella uses-_Laravel'));
+        $this->assertSame('Jefferson Costella Uses Laravel', Str::headline('jefferson_costella uses__Laravel'));
+
+        $this->assertSame('Laravel P H P Framework', Str::headline('laravel_p_h_p_framework'));
+        $this->assertSame('Laravel P H P Framework', Str::headline('laravel _p _h _p _framework'));
+        $this->assertSame('Laravel Php Framework', Str::headline('laravel_php_framework'));
+        $this->assertSame('Laravel Ph P Framework', Str::headline('laravel-phP-framework'));
+        $this->assertSame('Laravel Php Framework', Str::headline('laravel  -_-  php   -_-   framework   '));
+
+        $this->assertSame('Foo Bar', Str::headline('fooBar'));
+        $this->assertSame('Foo Bar', Str::headline('foo_bar'));
+        $this->assertSame('Foo Bar Baz', Str::headline('foo-barBaz'));
+        $this->assertSame('Foo Bar Baz', Str::headline('foo-bar_baz'));
+    }
+
     public function testStringWithoutWordsDoesntProduceError()
     {
         $nbsp = chr(0xC2).chr(0xA0);