public function build()
    {

        $query_params = [];

        $query_params["query"] = $this->q;

        if($this->boost > 1) {
            $query_params["boost"] = $this->boost;
        }

        if(count($this->fields)){
            $query_params["fields"] = $this->fields;
        }

        $this->query->must[] = [
            "query_string" => $query_params
        ];
    }