Smile\ElasticsuiteCore\Index\Mapping\Field::getMultiFieldMappingPropertyConfig PHP Method

    private function getMultiFieldMappingPropertyConfig($analyzers)
    {
        // Setting the field type to "multi_field".
        $property = ['type' => self::FIELD_TYPE_MULTI];
        foreach ($analyzers as $analyzer) {
            // Using the analyzer name as subfield name by default.
            $subFieldName = $analyzer;
            if ($analyzer == self::ANALYZER_STANDARD && $this->isNested()) {
                // Using the field suffix as default subfield name for nested fields.
                $subFieldName = $this->getNestedFieldName();
            } elseif ($analyzer == self::ANALYZER_STANDARD) {
                // Using the field name as default subfield name for normal fields.
                $subFieldName = $this->getName();
            }
            $property['fields'][$subFieldName] = $this->getPropertyConfig($analyzer);
        }
        return $property;
    }