public function getElements()
    {
        if (self::$elements === null) {
            self::$elements = $this->loadJson($this->resource('OptionalElements.json'))->elements;
        }

        return self::$elements;
    }
public function getElements()
    {
        if (self::$elements === null) {
            self::$elements = $this->loadJson($this->resource('OptionalElements.json'))->elements;
        }

        return self::$elements;
    }
public function getElements ( ) { if ( self :: $ elements === null ) { self :: $ elements = $ this -> loadJson ( $ this -> resource ( 'OptionalElements.json' ) ) -> elements ; } return self :: $ elements ; }
Get the optional html elments.

@throws \ArjanSchouten\HtmlMinifier\Exception\FileNotFoundException

@return mixed
Get the optional html elments .