toMap method
Implementation
Map<String, dynamic> toMap() => {
'@type': 'Offer',
'price': price,
'priceCurrency': currency,
if (availability != null) 'availability': availability!.url,
if (url != null) 'url': url,
if (validUntil != null) 'priceValidUntil': validUntil,
if (itemCondition != null) 'itemCondition': itemCondition!.url,
if (seller != null) 'seller': {'@type': 'Organization', 'name': seller},
};