Swift: is it possible to iterate and call an array of functions? - swift4

Question

I am trying to simplify the following repetitive code:
var cells = [Cell]()
var modules = [Module]()
var fields = [Field]()
root.child("cells").observeSingleEvent(of: .value) { (snapshot) in
guard let dict = snapshot.value as? [String: Any],
let cell = Cell(dict: dict) else { return }
cells.append(cell)
}
root.child("modules").observeSingleEvent(of: .value) { (snapshot) in
guard let dict = snapshot.value as? [String: Any],
let module = Module(dict: dict) else { return }
modules.append(module)
}
root.child("fields").observeSingleEvent(of: .value) { (snapshot) in
guard let dict = snapshot.value as? [String: Any],
let field = Field(dict: dict) else { return }
fields.append(field)
}
Cell, Module, Field are custom struct. I am thinking whether it's possible to put their initiators init?(dict: [String: Any]) in an array and pass in dict to each of them.

Answer 1

I think you will need to make your structs adopt one protocol for that:
protocol InitializableWithDictionary {
init?(dict: [String : Any])
}
struct Cell: InitializableWithDictionary {
//...
init?(dict: [String : Any]){
//...
}
}
struct Module: InitializableWithDictionary {
//...
init?(dict: [String : Any]){
//...
}
}
struct Field: InitializableWithDictionary {
//...
init?(dict: [String : Any]){
//...
}
}
var cells: [InitializableWithDictionary] = [Cell]()
var modules: [InitializableWithDictionary] = [Module]()
var fields: [InitializableWithDictionary] = [Field]()
root.child("cells").observeSingleEvent(of: .value) { (snapshot) in
guard let dict = snapshot.value as? [String: Any] else { return }
let array: [InitializableWithDictionary.Type] = [Cell.self, Module.self, Field.self]
array.forEach {
if let element = $0.init(dict: dict) {
switch element {
case is Cell: cells.append(element)
case is Module: modules.append(element)
case is Field: fields.append(element)
default: break
}
} else { return }
}
}