Smile\ElasticsuiteCatalog\Model\Product\Indexer\Fulltext\Datasource\AttributeData::addData PHP Method

    public function addData($storeId, array $indexData)
    {
        $productIds = array_keys($indexData);
        $indexData = $this->addAttributeData($storeId, $productIds, $indexData);
        $relationsByChildId = $this->resourceModel->loadChildrens($productIds);
        if (!empty($relationsByChildId)) {
            $allChildrenIds = array_keys($relationsByChildId);
            $childrenIndexData = $this->addAttributeData($storeId, $allChildrenIds);
            foreach ($relationsByChildId as $childId => $relations) {
                foreach ($relations as $relation) {
                    $parentId = (int) $relation['parent_id'];
                    if (isset($indexData[$parentId]) && isset($childrenIndexData[$childId])) {
                        $indexData[$parentId]['children_ids'][] = $childId;
                        $this->addRelationData($indexData[$parentId], $childrenIndexData[$childId], $relation);
                        $this->addChildData($indexData[$parentId], $childrenIndexData[$childId]);
                    }
                }
            }
        }
        return $indexData;
    }