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𝑓(x) FunctionalAPI

Some collection of functions and types that are useful in day to day development.



To help a bit with composability some existing map functions defined on Array and Result are made as global symbols.

public func map<A,B>(_ a: [A], _ f: (A) -> B) -> [B] { ... 

public func map<A,B>(_ a: Result<A,Error> , _ f: (A) -> B) -> Result<B, Error> { ...

Map on Optionals

Please chceck OptionalAPI Swift Package for maps and other extensions on Optional.


Whole implementation looks like this:

func identity<A>(_ a: A) -> A { a }

This might seem as a useless function but every time you write in your code { $0 } you are writing this exact same function. Let's see some example:

[1,2,3].map{ $0 } // [1,2,3]

Same cane be done with identity but with extra clarity:

[1,2,3].map( identity ) // [1,2,3]

Where this function is useful?

It depends what you need. I use it to generate variations in my snapshot tests. One array contains device, other size class, language direction... you get the idea ;)

🐇🕳 Rabbit Hole

This project is part of the 🐇🕳 Rabbit Hole Packages Collection


  • Swift Tools 5.6.0
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Last updated: Tue Jan 31 2023 20:50:15 GMT-0500 (GMT-05:00)