Why is the typical JSON handling in Swift NOT good?

iflet statusesArray=try?JSONSerialization.jsonObject(with: data, options:.allowFragments)as?[[String:Any]],let user=statusesArray[0]["user"]as?[String:Any],let username=user["name"]as?String{    // Finally we got the username}

iflet JSONObject=tryJSONSerialization.jsonObject(with: data, options:.allowFragments)as?[[String:Any]],let username=(JSONObject[0]["user"]as?[String:Any])?["name"]as?String{        // There's our username}

letjson=try?JSON(data: dataFromNetworking)iflet userName=json[0]["user"]["name"].string{  //Now you got your value}

letjson=try?JSON(data: dataFromNetworking)letresult=json[999999]["wrong_key"]["wrong_name"]iflet userName= result.string{    //Calm down, take it easy, the ".string" property still produces the correct Optional String type with safety}else{    //Print the errorprint(result.error)}

Requirements

Integration

CocoaPods (iOS 8+, OS X 10.9+)

platform:ios,'8.0'use_frameworks!target'MyApp'dopod'SwiftyJSON','~> 4.0'end

Carthage (iOS 8+, OS X 10.9+)

github "SwiftyJSON/SwiftyJSON" ~> 4.0

Swift Package Manager

// swift-tools-version:4.0import PackageDescriptionletpackage=Package(    name:"YOUR_PROJECT_NAME",    dependencies:[.package(url:"https://github.com/SwiftyJSON/SwiftyJSON.git", from:"4.0.0"),])

Manually (iOS 7+, OS X 10.9+)

Usage

Initialization

import SwiftyJSON

letjson=try?JSON(data: dataFromNetworking)

letjson=JSON(jsonObject)

iflet dataFromString= jsonString.data(using:.utf8, allowLossyConversion:false){letjson=JSON(data: dataFromString)}

Subscript

// Getting a double from a JSON Arrayletname=json[0].double

// Getting an array of string from a JSON ArrayletarrayNames=json["users"].arrayValue.map{$0["name"].stringValue}

// Getting a string from a JSON Dictionaryletname=json["name"].stringValue

// Getting a string using a path to the elementletpath:[JSONSubscriptType]=[1,"list",2,"name"]letname=json[path].string// Just the sameletname=json[1]["list"][2]["name"].string// Alternativelyletname=json[1,"list",2,"name"].string

// With a hard wayletname=json[].string

// With a custom wayletkeys:[JSONSubscriptType]=[1,"list",2,"name"]letname=json[keys].string

Loop

// If json is .Dictionaryfor(key,subJson):(String,JSON)in json{   // Do something you want}

// If json is .Array// The `index` is 0..<json.count's string valuefor(index,subJson):(String,JSON)in json{    // Do something you want}

Error

SwiftyJSON 4.x

SwiftyJSON 3.x

letjson=JSON(["name","age"])iflet name=json[999].string{    // Do something you want}else{print(json[999].error!) // "Array[999] is out of bounds"}

letjson=JSON(["name":"Jack","age":25])iflet name=json["address"].string{    // Do something you want}else{print(json["address"].error!) // "Dictionary["address"] does not exist"}

letjson=JSON(12345)iflet age=json[0].string{    // Do something you want}else{print(json[0])       // "Array[0] failure, It is not an array"print(json[0].error!) // "Array[0] failure, It is not an array"}iflet name=json["name"].string{    // Do something you want}else{print(json["name"])       // "Dictionary[\"name"] failure, It is not an dictionary"print(json["name"].error!) // "Dictionary[\"name"] failure, It is not an dictionary"}

Optional getter

// NSNumberiflet id=json["user"]["favourites_count"].number{   // Do something you want}else{   // Print the errorprint(json["user"]["favourites_count"].error!)}

// Stringiflet id=json["user"]["name"].string{   // Do something you want}else{   // Print the errorprint(json["user"]["name"].error!)}

// Booliflet id=json["user"]["is_translator"].bool{   // Do something you want}else{   // Print the errorprint(json["user"]["is_translator"].error!)}

// Intiflet id=json["user"]["id"].int{   // Do something you want}else{   // Print the errorprint(json["user"]["id"].error!)}...

Non-optional getter

// If not a Number or nil, return 0letid:Int=json["id"].intValue

// If not a String or nil, return ""letname:String=json["name"].stringValue

// If not an Array or nil, return []letlist:Array<JSON>=json["list"].arrayValue

// If not a Dictionary or nil, return [:]letuser:Dictionary<String,JSON>=json["user"].dictionaryValue

Setter

json["name"]=JSON("new-name")json[0]=JSON(1)

json["id"].int=1234567890json["coordinate"].double=8766.766json["name"].string="Jack"json.arrayObject=[1,2,3,4]json.dictionaryObject=["name":"Jack","age":25]

Raw object

letrawObject:Any= json.object

letrawValue:Any= json.rawValue

//convert the JSON to raw NSDatado{letrawData=try json.rawData()  //Do something you want}catch{print("Error\(error)")}

//convert the JSON to a raw Stringiflet rawString= json.rawString(){  //Do something you want}else{print("json.rawString is nil")}

Existence

// shows you whether value specified in JSON or notifjson["name"].exists()

Literal convertibles

// StringLiteralConvertibleletjson:JSON="I'm a json"

// IntegerLiteralConvertibleletjson:JSON=12345

// BooleanLiteralConvertibleletjson:JSON=true

// FloatLiteralConvertibleletjson:JSON=2.8765

// DictionaryLiteralConvertibleletjson:JSON=["I":"am","a":"json"]

// ArrayLiteralConvertibleletjson:JSON=["I","am","a","json"]

// With subscript in arrayvarjson:JSON=[1,2,3]json[0]=100json[1]=200json[2]=300json[999]=300 // Don't worry, nothing will happen

// With subscript in dictionaryvarjson:JSON=["name":"Jack","age":25]json["name"]="Mike"json["age"]="25" // It's OK to set Stringjson["address"]="L.A." // Add the "address": "L.A." in json

// Array & Dictionaryvarjson:JSON=["name":"Jack","age":25,"list":["a","b","c",["what":"this"]]]json["list"][3]["what"]="that"json["list",3,"what"]="that"letpath:[JSONSubscriptType]=["list",3,"what"]json[path]="that"

// With other JSON objectsletuser:JSON=["username":"Steve","password":"supersecurepassword"]letauth:JSON=["user": user.object, // use user.object instead of just user"apikey":"supersecretapitoken"]

Merging

letoriginal:JSON=["first_name":"John","age":20,"skills":["Coding","Reading"],"address":["street":"Front St","zip":"12345",]]letupdate:JSON=["last_name":"Doe","age":21,"skills":["Writing"],"address":["zip":"12342","city":"New York City"]]letupdated= original.merge(with: update)// [//     "first_name": "John",//     "last_name": "Doe",//     "age": 21,//     "skills": ["Coding", "Reading", "Writing"],//     "address": [//         "street": "Front St",//         "zip": "12342",//         "city": "New York City"//     ]// ]

Removing elements

varobject=JSON(["one":["color":"blue"],"two":["city":"tokyo","country":"japan","foods":["breakfast":"tea","lunch":"sushi"]]])

object["two"].dictionaryObject?.removeValue(forKey:"country")

{"one" : {"color" :"blue"  },"two" : {"city" :"tokyo","foods" : {"breakfast" :"tea","lunch" :"sushi"    }  }}

object["two"]["foods"].dictionaryObject?.removeValue(forKey:"breakfast")

{"one" : {"color" :"blue"  },"two" : {"city" :"tokyo","foods" : {"lunch" :"sushi"    }  }}

String representation

letdict=["1":2,"2":"two","3":nil]as[String:Any?]letjson=JSON(dict)letrepresentation= json.rawString(options:[.castNilToNSNull:true])// representation is "{\"1\":2,\"2\":\"two\",\"3\":null}", which represents {"1":2,"2":"two","3":null}

Work withAlamofire

Alamofire.request(url, method:.get).validate().responseJSON{ responseinswitch response.result{case.success(let value):letjson=JSON(value)print("JSON:\(json)")case.failure(let error):print(error)}}

Work withMoya

letprovider=MoyaProvider<Backend>()provider.request(.showProducts){ resultinswitch result{caselet.success(moyaResponse):letdata= moyaResponse.dataletjson=JSON(data: data) // convert network data to jsonprint(json)caselet.failure(error):print("error:\(error)")}}

SwiftyJSON Model Generator