Hands on with some nice Medium articles dealing with aspects, curiosities and hidden functionalities about swift:

• Autoclosures
• GCD: Semaphores, DispatchWorkItem
• OperationQueue: performing requests in parallel
• Optionals: handling nil and "" in String?
• Generic: struct extension using generics and generics with protocols
• Playgrounds: animations live rendering
• Dependeny Injection: using the cake pattern
• Local reasoning: improving swift readibility
• Create a generic networking API based on protocols and codable
• Tuples interesting features
• Swift hidden features
• Design patterns in Swift