createAggregation example

public function parseAggregation(Aggregation $aggregation, EntityDefinition $definition, Context $context): ?AbstractAggregation
    {
        $fieldName = $this->buildAccessor($definition, $aggregation->getField(), $context);

        $fields = $aggregation->getFields();

        $path = null;
        if (\count($fields) > 0) {
            $path = $this->getNestedPath($definition, $fields[0]);
        }

        $esAggregation = $this->createAggregation($aggregation, $fieldName, $definition, $context);

        if (!$path || $aggregation instanceof FilterAggregation) {
            return $esAggregation;
        }

        $nested = new NestedAggregation($aggregation->getName(), $path);
        $nested->addAggregation($esAggregation);

        return $nested;
    }