Isswp101\Persimmon\QueryBuilder\QueryBuilder::fields PHP Method

    public function fields($fields = false)
    {
        if ($fields === false) {
            $this->query['body']['_source'] = false;
        } elseif ((array) $fields == ['*']) {
            unset($this->query['body']['_source']);
        } else {
            $this->query['body']['_source'] = $fields;
        }
        return $this;
    }