Item::convertFieldId

static function convertFieldId(string $fieldId, int $convertTo = self::CONVERT_TO_BP): string
{
	$map = [
		Crm\Item::FIELD_NAME_OBSERVERS => 'OBSERVER_IDS',
		Crm\Item::FIELD_NAME_PRODUCTS => 'PRODUCT_IDS',
	];

	if ($fieldId === Crm\Item::FIELD_NAME_CONTACTS)
	{
		return 'CONTACT_IDS';
	}
	if ($convertTo === self::CONVERT_TO_DOCUMENT)
	{
		$map = array_flip($map);
	}

	return array_key_exists($fieldId, $map) ? $map[$fieldId] : $fieldId;
}