move_uploaded_file To Current Path - PHP

$allowed_extensions = ['gif', 'jpg', 'jpeg', 'png', 'pdf'];
$filename = basename($_FILES['file']['name']);
$extension = strtolower(pathinfo($filename, PATHINFO_EXTENSION));

if (!in_array($extension, $allowed_extensions, true)) {
    echo "File type not allowed.\n";
    exit;
}

$uploadfile = './' . $filename;

if (move_uploaded_file($_FILES['file']['tmp_name'], $uploadfile)) {
    echo "File was successfully uploaded.\n";
} else {
    echo "There was an issue uploading the file.\n";
}