# Singleton class with custom initializer

In a Swift project, I have a class should be used as a singleton:

  class NearFieldManager : NSObject{
static let shared = NearFieldManager()
var dataToTransfer:Any!
}


This class helps me communicate between several nearby devices and the dataToTransfer is some information each device is advertising about itself. What makes me wondering about this class is that each time I call it goes like this:

let manager = NearFieldManager.shared
shared.dataToTransfer = "some data"


First, I am creating a reference to the manager and line after it I set some value on its property. How can I improve this design?

Assuming the dataToTransfer is always the same for a specific device, you can create this data in init()

class NearFieldManager {
static let shared = NearFieldManager()
private let dataToTransfer: Any

private init() { //private to forbid instantiation
self.dataToTransfer = methodToCreateDeviceData()
}
}

• I'd get rid of that redundant dataToTransfer local var. It doesn't contribute anything but visual clutter. – Alexander - Reinstate Monica Jan 23 '17 at 21:15
• @Alexander agree. – shallowThought Jan 24 '17 at 3:17