JSONNode

A simple, Swifty way to interact with JSON.

JSONNode is simple, useful, and under 150 lines of code.

Advantage over traditional JSON handling

Let’s take the response from the ImgFlip Meme API

{
    "success": true,
    "data": {
        "memes": [
              {
                  "id": "61579",
                  "name": "One Does Not Simply",
                  "url": "http://i.imgflip.com/1bij.jpg",
                  "width": 568,
                  "height": 335
              },
              {
                  "id": "101470",
                  "name": "Ancient Aliens",
                  "url": "http://i.imgflip.com/26am.jpg",
                  "width": 500,
                  "height": 437
              }
          ]
    }
}

To retrieve the name for the first meme, you would do the following:

var jsonObject = try! JSONSerialization.jsonObject(with: jsonData, options: [.allowFragments])

guard
    let jsonDictionary = jsonObject as? [String: Any],
    let dataDictionary = jsonDictionary["data"] as? [String: Any],
    let memesArray = dataDictionary["memes"] as? [[String: Any]],
    let firstMeme = memesArray.first,
    let memeName = firstMeme["name"] as? String else {

        fatalError()
}

print(memeName)

With JSONNode this becomes the following:

var jsonNode = JSONNode(data: jsonData)!
guard let name = jsonNode["data"]["memes"][0]["name"].string else { fatalError() }

print(name)

How it works

Typically when JSON is deserialised, it is turned into nested arrays and dictionary, and since these collections need a type and the JSON could contain any of multiple types, the non-specific Any protocol is used.

This is not a true representation of the situation though. There can’t be “anything” in the collection. Each node in the JSON structure can only be one of the following:

• String
• Boolean
• Integer
• Floating point number
• Array containing something in this list
• Dictionary with a string key and value as something in this list

With this finite list of possible values for a JSON node, a enum is the best way to represent that. Inspiration was taken from the way that Swift Playgrounds passes information been the playground page and the live view.

Requirements

• iOS 8.0+ | macOS 10.7+ | tvOS 9.0+ | watchOS 2.0+
• Swift 3
• Xcode 8

Integration

Manually (iOS 8+, OS X 10.9+)

To use this library in your project manually you may:

1. for Projects, just drag JSONNode.swift to the project tree
2. for Workspaces, include the whole JSONNode.xcodeproj