Yaml front matter not passing the body to the ddd()

Hello, I need some assistance. I'm following the beginners tutorial for Laravel and up to the section on Yaml front matter.

For some reason I cannot work out, the body of the array is showing up as null, but the meta data is being passed through.

My route looks like this

Route::get('/', function () {

    $files = File::files(resource_path("/posts"));
    $posts = [];

    foreach ($files as $file) {
        $document = YamlFrontMatter::parseFile($file);
        $posts[] = new Post(
            $document->title,
            $document->excerpt,
            $document->date,
            $document->body,
        );
    };

    ddd($posts);
});

And my controller class looks like this:

class Post
{

    public $title;

    public $excerpt;

    public $date;

    public $body;

    /**
     * @param $title
     * @param $excerpt
     * @param $date
     * @param $body
     */
    public function __construct($title, $excerpt, $date, $body)
    {
        $this->title = $title;
        $this->excerpt = $excerpt;
        $this->date = $date;
        $this->body = $body;
    }


    public static function all()
    {
        $files = File::files(resource_path("/posts"));

        return array_map(fn($file) => $file->getContents(), $files);
    }
}   

Can you please help me work out why the body is showing up as null in the ddd() of the array?

PS -> debug looks like this:

array:3 [▼
  0 => App\Models\Post {#275 ▼
    +title: "My First Post"
    +except: "Lorem ipsum text that I have chosen..."
    +date: 1669593600
    +body: null
  }
  1 => App\Models\Post {#276 ▶}
  2 => App\Models\Post {#287 ▶}
]