SwiftJSONi

Why SwiftJSONi?

The traditional way of handling JSON in Swift is so cumbersome and requires many lines of code. For example, consider a JSON response from a API for bakery items,

{
    "items": {
        "item": [
            {
                "id": "0001",
                "type": "donut",
                "name": "Cake",
                "ppu": 0.55,
                "batters": {
                "batter": [
                        { "id": "1001", "type": "Regular" },
                        { "id": "1002", "type": "Chocolate" },
                        { "id": "1003", "type": "Blueberry" },
                        { "id": "1004", "type": "Devil's Food" }
                    ]
                },
                "topping": [
                    { "id": "5001", "type": "None" },
                    { "id": "5002", "type": "Glazed" },
                    { "id": "5005", "type": "Sugar" },
                    { "id": "5007", "type": "Powdered Sugar" },
                    { "id": "5006", "type": "Chocolate with Sprinkles" },
                    { "id": "5003", "type": "Chocolate" },
                    { "id": "5004", "type": "Maple" }
                ]
            }
        ]
    }
}

To get the type of 4th topping in first item, the safest Swift code looks like,

if let json = try? JSONSerialization.jsonObject(with: jsonData, options: .allowFragments) as? [String: Any],
    let items = object["items"] as? [String: Any],
    let item = items["item"] as? [[String: Any]],
    let firstItem = item.first,
    let toppings = firstItem["topping"] as? [[String: Any]],
    toppings.count >= 3,
    let type = toppings[3]["type"] as? String
{
    print(type)
}

It involves lots of typecasting and safe index checks due to Swift's strict typecast and array index policies. To achieve the same with SwiftJSONi, the code looks like,

if let json = JSON(data: jsonData),
    let type = json["items"]["item"][0]["topping"][3]["type"].string
{
    print(type)
}

That's it!! It is so safe and readable. No need to worry about type casting and array index checks. It is all done automatically.

Installation

SwiftJSONi is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'SwiftJSONi'

Usage

Initialization

import SwiftJSONi

let data: Data? // Response from API
let json = JSON(data: data) // Returns JSON?

let any: Any? // Value of Any type
let json = JSON(any) // Returns JSON?

let dictionary: [String: Any]
let json = JSON(dictionary) // Returns JSON

let validatedJSON = JSON(validateObject: dictionary) // Returns JSON?   
        // Returns 'nil' when a value for key has unsupported JSON type.

Accessing values

Consider the bakery items JSON in the above example. Accessing the 'id' of first item be like,

let firstItem = json["items"]["item"][0] 
let id = firstItem["id"].string

Difference between .string and .stringValue is,

.string - Returns the String value if available else returns nil

.stringValue - Returns the String value if available else returns default value i.e "" (empty String)

So, getting the 'ppu' of first item belike,

let ppu = firstItem["ppu"].floatValue  

Methods

For String,

string	Returns the String value if available else returns nil
stringValue	Returns the String value if available else returns default value i.e "" (empty String)

For Int,

int	Returns the Int value if available else returns nil
intValue	Returns the Int value if available else returns default value i.e 0

For Float,

float	Returns the Float value if available else returns nil
floatValue	Returns the Float value if available else returns default value i.e 0.0

For Double,

double	Returns the Double value if available else returns nil
doubleValue	Returns the Double value if available else returns default value i.e 0.0

For Bool,

bool	Returns the Bool value if available else returns nil
boolValue	Returns the Bool value if available else returns default value i.e false

For JSON Object,

jsonObject	Returns [String: JSON]?
jsonObjectValue	Returns [String: JSON] else [:]

For JSON Array,

jsonArray	Returns [JSON]?
jsonArrayValue	Returns [JSON] else []

For Array,

array	Returns [Any?]
arrayValue	Returns [Any?] else []

For Dictionary,

dictionary	Returns [String: Any]?
dictionaryValue	Returns [String: Any] else [:]

Type Checks

Since JSON is a custom type, typecasting it to primitive types always fails, i.e,

let name = json["name"] as? String  // Always fails.

So is,

if json["name"] is String {  // Condition always fails.
    // Do something
}

Hence, SwiftJSONi uses inbuilt properties to check the type of values. Only these types will be accepted by JSON. Any other user-defined types cannot be used as JSON value.

isNull	Returns true if the value is nil.
isString	Returns true if the value is String.
isInt	Returns true if the value is Int.
isFloat	Returns true if the value is Float.
isDouble	Returns true if the value is Double.
isBool	Returns true if the value is Bool.
isJsonObject	Returns true if the value is [String: JSON].
isJsonArray	Returns true if the value is [JSON].
isArray	Returns true if the value is [Any?].
isDictionary	Returns true if the value is [String: Any].

So the above situations can be handled as,

if json["name"].isString {
    // Do something
}

Debugging

debugPrint() is used to pretty print the JSON in console. description is the valid JSON String for the corresponding JSON.

Author

Akaash Dev, heatblast.akaash@gmail.com

License

SwiftJSONi is available under the MIT license. See the LICENSE file for more info.