Swift Protocols

Equatable

It’s a good idea for all your custom model types to conform.
With Equatable conformance, you can use the equal-to operator (==) or the not-equal-to operator (!=) with any two instances
To make a class conform to the Equatable protocol, declare conformance in an extension and implement the static == operator method. Compare each significant property for equality in your == method’s implementation:

extension Player: Equatable {
 static func ==(lhs: Player, rhs: Player) -> Bool {
  return lhs.name == rhs.name && lhs.position == rhs.position } }

It’s a good idea for all your custom model types to conform.
To conform to the Hashable protocol, declare conformance in another extension and implement the hash(into:) method. In the hash(into:) method, call the combine(_:) method on the provided hasher with each significant property:

extension Player: Hashable {
 func hash(into hasher: inout Hasher) {
  hasher.combine(name)
  hasher.combine(position)
 }
}

*A type is eligible for automatic conformance to Equatable and Hashable when it’s a structure or an enumeration that meets these criteria:

For a structure, all its stored properties must conform to Equatable and Hashable.
For an enumeration, all its associated values must conform to Equatable and Hashable. (Enumerations without associated values have Equatable and Hashable conformance even without declaring adoption.)*
Always use the same properties in both your == and hash(into:) methods. Using different groups of properties in the two methods can lead to unexpected behavior or performance when using your custom type in sets and dictionaries.*