Dart provides the possibility to use getters and setters, special methods that give read and write access to an object's properties.
You can use a getter to hide write access to a property:
enum ProductType { normal, offer }
class Product {
// The product id.
final String id = "ABC1234";
// This property cannot be modified directly from outside the object.
ProductType _type;
Product(this._type);
// _type can be accessed read-only using this getter.
ProductType get type => _type;
}
You can also use them to calculate a certain value that is notdirectlystored in your object:
...
// Get whether the type of the product is an offer.
bool get isOffer => _type == ProductType.offer;
}
You could also use a method, instead of a getter:
...
// Get whether the type of the product is an offer.
bool isOffer() => _type == ProductType.offer;
}
So, how do you know where to use a getter and where to use a method?
Personally, I avoid using a getter when the value cannot be calculated in O(1)
. The reason is that a getter and a property look the same from the outside, from the point of view of the user of your object.
final product = Product(ProductType.offer);
// Is this a getter or a property?
product.id;
// Is this a getter or a property?
product.isOffer;
So the fact that there is a calculation behind the getter might be lost for the final user of the object who might think that the getter is a property and will use it as a O(1)
"function".
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