SwiftyJSON

by Online Tutorials Library July 14, 2022

SwiftyJSON

SwiftyJSON is an open-source library that helps developers use JSON in Swift without much difficulty. Swift is very strict about types so, it is very difficult to work with JSON in Swift. SwiftyJSON provides a better way to deal with JSON data in Swift.

SwiftyJSON is a Swift framework which was built to remove the need for optional chaining in normal JSON serialization.

The problem with JSON in Swift

Before using SwiftyJSON, let’s see the mess a user can face while dealing with JSON in Swift. For example, your code would look like this if you find the name of the first book in a JSON object:

    if let jsonObject = try NSJSONSerialization.JSONObjectWithData(data, options: .AllowFragments) as? [[String: AnyObject]],  let bookName = (jsonObject[0][“book”] as? [String: AnyObject])?[“name”] as? String {      //Now, you can use the book name  }  

You can see that the above code is complicated and difficult to read.

By using SwiftyJSON, it will be highly simplified like this:

  let json = JSON(data: data)  if let bookName = json[0][“book”][“name”].string {      //Now, you can use the book name  }  

SwiftyJSON removes the requirement of checking every field, as it returns nil if any of them are invalid.

Download SwiftJSON

You can download or clone SwityJSON directly from GitHub:

https://github.com/SwiftyJSON/SwiftyJSON

How to use SwiftyJSON

To use SwiftyJSON, you have to download the correct version from the Git repository. Simply, drag the “SwiftyJSON.swift” into your project and import into your class:

You can create your own JSON object by using initializers. There are two ways to create your own JSON object:

  let jsonObject = JSON(jsonObject) //This could be a string in a JSON format for example  

You can use subscripts to access your data.

  let firstObjectInAnArray = jsonObject[0]  let nameOfFirstObject = jsonObject[0][“name”]  

You can parse your value to a certain data type, which will return an optional value:

  let nameOfFirstObject = jsonObject[0][“name”].string //This will return the name as a string  let nameOfFirstObject = jsonObject[0][“name”].double //This will return null  

You can also compile your paths into a swift Array:

  let convolutedPath = jsonObject[0][“name”][2][“lastName”][“firstLetter”].string   

It is same as:

  let convolutedPath = jsonObject[0, “name”, 2, “lastName”, “firstLetter”].string  

SwiftyJSON has the functionality to print its own errors:

  if let name = json[1337].string {      //You can use the value – it is valid  } else {      print(json[1337].error) // “Array[1337] is out of bounds” – You cant use the value  }  

If you need to write to your JSON object, you can use subscripts again:

  var originalJSON:JSON = [“name”: “Jack”, “age”: 18]  originalJSON[“age”] = 25 //This changes the age to 25  originalJSON[“surname”] = “Smith” //This creates a new field called “surname” and adds the value to it.  

If you want the original String for the JSON, for example if you need to write it to a file, you can get the raw value.

  if let string = json.rawString() { //This is a String object      //Write the string to a file if you like  }  if let data = json.rawData() { //This is an NSData object      //Send the data to your server if you like  }  

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