Tip and Tricks working with Swift's Optionals

14 Jul 2020

Optional is a very common type in Swift, but there are a couple of tips and tricks that I think could be useful

Optionals Can be `map`ed

The Optional type has both map(_:) and flatMap(_:) functions, which can allow code like:

if let url = url {
  loadURL(url)
}

to be:

url.map(loadURL(_:))

Checking if `Any` is an Optional

Sometimes you might need to write an API that takes an Any value and cast it to non-Any optional, e.g.:

let optionalStringAsAny: Any = Optional.some("String")
let optionalString = optionalStringAsAny as? String? // Don't do this

In this scenario the type of optionalString is String??.

So you might try:

let optionalStringAsAny: Any = Optional.some("String")
let optionalString = optionalStringAsAny as? String // Don't do this either

Something I find myself using more and more are the map(_:) and flatMap(_:) functions that are available on Swift’s Optional type.

This post is part of a series of posts discussing the Optional type in Swift. To view other posts on this subject view the swift-optional tag.