OutputFormatting = .sortedKeys

[VadimPavlov]

I believe there is no reason for @available in (legacy code from JSONEncoder?)
@available(macOS 10.13, iOS 11.0, watchOS 4.0, tvOS 11.0, *)
public static let sortedKeys = OutputFormatting(rawValue: 1 << 1)

[regexident]

You're absolutely right, @VadimPavlov!

It's a relict of the initial forking of stdlib's JSONCoding code.

I created a PR for it: #53

[MaxDesiatov]

Thanks for reporting this @VadimPavlov, #53 has been merged to master now and I believe this issue can be closed. Please feel free to reopen it with more details if needed.