Tisander

Ordered JSON parser in pure Swift

I needed a JSON parser that has all of the items in dictionaries to be sorted to work around an issue where an existing API couldn't be changed to return objects in an array. In my quest to find this, I noticed almost all parsers used JSONSerialization from Apple to create their dictionaries and the dictionaries (quite correctly) has no order, but it was not consistent. Different platforms (simulator vs device) would give different orders and this is not something I could accept in my work.

The parser is now pure Swift and returns an array of either JSON.ArrayValues or JSON.ObjectValues (depending on what the structure was when they were parsed). This can be accessed by subscripting a String or Int and then cast to get values. Most importantly for me, you can get .allKeys from the array of JSON.ObjectValues and they are sorted in the order they were in the JSON file because JSONSwift is: A JSON parser written from the ground up in pure Swift. It is a functional recursive descent parser.

Installing

Cocoapods

Add this to your Podfile

pod 'Tisander', '~> 1.0'

Manual

Copy JSON.swift file into your project. Or just import the framework. That's it. :)

How to use:

Parse JSON Object

// Data
let jsonString = """
{
    "Monday": [
        {
            "title": "Test Driven Development",
            "speaker": "Jason Shapiro",
            "time": "9:00 AM"
        },
        {
            "title": "Java Tools",
            "speaker": "Jim White",
            "time": "9:00 AM"
        }
    ],
    "Tuesday": [
        {
            "title": "MongoDB",
            "speaker": "Davin Mickleson",
            "time": "1:00 PM"
        },
        {
            "title": "Debugging with Xcode",
            "speaker": "Jason Shapiro",
            "time": "1:00 PM"
        }
    ]
}
"""

Call the static method JSON.parse(string:) with the jsonString string, and use optional chaining to get the values you want:

var parsedJSON: Value?

do {
    parsedJSON = try JSON.parse(string: jsonString)
} catch let error {
    print("Could not parse JSON because of error: \(error)")
}

let keys = parsedJSON?.keys
print(keys?.joined(separator: ", ") ?? "")

// Prints:
//  Monday, Tuesday

let mondayValues = parsedJSON?["Monday"]?.values

mondayValues?.forEach({ (day) in
    print((day["title"] as? String) ?? "")
})

// Prints:
//  Test Driven Development
//  Java Tools

Authors

Tisander author:

Mike Bignell

JSONSwift authors:

Ankit Goel

Kartik Yelchuru