Simple sample of using Map & FlatMap On Optionals

Optional_FlatMap_Example.swift

var str: String?
        
let result0 = str.flatMap { Int($0) }.valueOrDefault(.min)
        
var result1: Int = .min
if let str = str {
   result1 = Int(str) ?? .min
}
// result1 can be changed here, but result0 can't. 
assert(result0 == result1)

//Similar can be done using "map" method