Swift Language Generics Use generics to enhance type-safety
Example
Let's take this example without using generics
protocol JSONDecodable {
static func from(_ json: [String: Any]) -> Any?
}
The protocol declaration seems fine unless you actually use it.
let myTestObject = TestObject.from(myJson) as? TestObject
Why do you have to cast the result to TestObject? Because of the Any return type in the protocol declaration.
By using generics you can avoid this problem that can cause runtime errors (and we don't want to have them!)
protocol JSONDecodable {
associatedtype Element
static func from(_ json: [String: Any]) -> Element?
}
struct TestObject: JSONDecodable {
static func from(_ json: [String: Any]) -> TestObject? {
}
}
let testObject = TestObject.from(myJson) // testObject is now automatically `TestObject?`
