Dictionary Map

Dictionary + mapD.swift

extension Dictionary {
    func mapD<T: Hashable, U>(_ elementClosure: ((key: T, value: U) -> (T, U))) -> Dictionary<T, U> {
        return self.map { (tuple) in
            return elementClosure(key: tuple.0 as! T, value: tuple.1 as! U) // The compiler demands these casts exist 😕
        }.toDictionary()
    }
}

extension Sequence {
    func toDictionary<T: Hashable, U>() -> Dictionary<T, U> {
        var returnDict = [T : U]()
        for i in self {
            let tuple = i as! (T, U)
            returnDict[tuple.0] = tuple.1
        }
        return returnDict
    }
}


let dict = [
    1: ["foo", "bar"],
    2: ["bar", "baz"]
]

let newDict = dict.mapD { (key, value) in
    (key, value.sorted())
}