#Alexander
Alexander is an extremely simple JSON helper written in Swift. It brings type safety and Foundation helpers to the cumbersome task of JSON unpacking.
Xcode | Swift | iOS | tvOS | OS X |
---|---|---|---|---|
7.3 | 2.2 | 8.0 | 9.0 | 10.9 |
github "hodinkee/alexander"
#####CocoaPods
pod 'Alexander'
Make a new DecoderType
that can unpack your object.
struct User {
var ID: String
var name: String
var email: String
}
struct UserDecoder: DecoderType {
typealias Value = User
static func decode(JSON: Alexander.JSON) -> Value? {
guard
let ID = JSON["id"]?.stringValue,
let name = JSON["name"]?.stringValue,
let email = JSON["email"]?.stringValue
else {
return nil
}
return User(ID: ID, name: name, email: email)
}
}
Now you can do let author = JSON["user"]?.decode(UserDecoder)
to get a single user, or let users = JSON["users"]?.decodeArray(UserDecoder)
to get an array of users.
You can make DecodableType
s for all kinds of things.
struct SizeDecoder {
typealias Value = CGSize
static func decode(JSON: Alexander.JSON) -> Value? {
guard
let width = JSON["width"]?.doubleValue,
let height = JSON["height"]?.doubleValue
else {
return nil
}
return CGSize(width: width, height: height)
}
}
Alexander ships with a handful of decoders for common types:
NSDateTimeIntervalSince1970Decoder
NSDateTimeIntervalSinceReferenceDateDecoder
NSURLDecoder
RawRepresentableDecoder
Most of Alexander's power comes from its two subscript operators: subscript[key: String] -> JSON?
and subscript[index: Int] -> JSON?
. These operators allow you to unpack nested objects without having to refer to each intermediate step by hand. Something like let nextCursor = JSON["meta"]?["pagination"]?["next_cursor"]?.stringValue
is a single line of code.
You can also decode anything that conforms to the RawRepresentable
type. For example, assume the following enum:
enum Planet: String {
case Mercury = "mercury"
case Venus = "venus"
case Earth = "earth"
case Mars = "mars"
case Jupiter = "jupiter"
case Saturn = "saturn"
case Uranus = "uranus"
case Neptune = "neptune"
// case Pluto = "pluto" =(
}
Because Planet
is backed by a String
raw value type, it is inheriently RawRepresentable
. This means you can do let planet = JSON["planet"]?.decode(RawRepresentableDecoder<Planet>)
or let planets = JSON["planets"]?.decodeArray(RawRepresentableDecoder<Planet>)
.