O

optional

component MostDataTypeOptional

Component AdafDataTypeOptionals

Standard compliant implementation of optional<T>

swift 3+ optional Warp extension for string and array ,and use infix operator ??? . source : https://medium.com/@JanLeMann/providing-meaningful-default-values-for-empty-or-absence-optionals-via-nil-or-empty-coalescing-379abd22ae77