Decode Array<Any> and Dictionary<String, Any>.Swift

//
//  CodableExtensions.swift
//  7-Eleven
//
//  Created by Raja Sekhar Chiderae on 1/14/19.
//  Copyright © 2019 self. All rights reserved.
//

import Foundation

// Inspired by https://gist.github.com/loudmouth/332e8d89d8de2c1eaf81875cfcd22e24
// Used to decode dictionaries and array of dictionaries

struct JSONCodingKeys: CodingKey {
	var stringValue: String
	var intValue: Int?

	init(stringValue: String) {
		self.stringValue = stringValue
	}

	init?(intValue: Int) {
		self.init(stringValue: "\(intValue)")
		self.intValue = intValue
	}
}

extension KeyedDecodingContainer {

	func decode(_ type: [String: Any].Type, forKey key: K) throws -> [String: Any] {
		let container = try self.nestedContainer(keyedBy: JSONCodingKeys.self, forKey: key)
		return try container.decode(type)
	}

	func decodeIfPresent(_ type: [String: Any].Type, forKey key: K) throws -> [String: Any]? {
		guard contains(key) else {
			return nil
		}
		return try decode(type, forKey: key)
	}

	func decode(_ type: [Any].Type, forKey key: K) throws -> [Any] {
		var container = try self.nestedUnkeyedContainer(forKey: key)
		return try container.decode(type)
	}

	func decode(_ type: [[String: Any]].Type, forKey key: K) throws -> [[String: Any]] {
		var container = try self.nestedUnkeyedContainer(forKey: key)
		return try container.decode(type)
	}

	func decodeIfPresent(_ type: [Any].Type, forKey key: K) throws -> [Any]? {
		guard contains(key) else {
			return nil
		}
		return try decode(type, forKey: key)
	}

	func decode(_ type: [String: Any].Type) throws -> [String: Any] {
		var dictionary = [String: Any]()

		for key in allKeys {
			if let boolValue = try? decode(Bool.self, forKey: key) {
				dictionary[key.stringValue] = boolValue
			} else if let intValue = try? decode(Int.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(Int8.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(Int16.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(Int32.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(Int64.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(UInt.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(UInt8.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(UInt16.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(UInt32.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let intValue = try? decode(UInt64.self, forKey: key) {
				dictionary[key.stringValue] = intValue
			} else if let doubleValue = try? decode(Float.self, forKey: key) {
				dictionary[key.stringValue] = doubleValue
			} else if let doubleValue = try? decode(Double.self, forKey: key) {
				dictionary[key.stringValue] = doubleValue
			} else if let stringValue = try? decode(String.self, forKey: key) {
				dictionary[key.stringValue] = stringValue
			} else if let nestedDictionary = try? decode(Dictionary<String, Any>.self, forKey: key) {
				dictionary[key.stringValue] = nestedDictionary
			} else if let nestedArray = try? decode(Array<Any>.self, forKey: key) {
				dictionary[key.stringValue] = nestedArray
			} else if let value = try? decodeNil(forKey: key), value {
				//saving NSNull values in a dictionary will produce unexpected results for users, just skip
			}
		}
		return dictionary
	}
	
	func decodeIfPresent<T: Decodable>(forKey key: K, defaultValue: T) -> T {
		do {
			//below will throw
			return try self.decodeIfPresent(T.self, forKey: key) ?? defaultValue
		} catch {
			return defaultValue
		}
	}

}

extension UnkeyedDecodingContainer {

	mutating func decode(_ type: [[String: Any]].Type) throws -> [[String: Any]] {
		var array: [[String: Any]] = []
		while isAtEnd == false {
			if let nestedDictionary = try? decode(Dictionary<String, Any>.self) {
				array.append(nestedDictionary)
			}
		}
		return array
	}

	mutating func decode(_ type: [Any].Type) throws -> [Any] {
		var array: [Any] = []
		while isAtEnd == false {
			if let value = try? decode(Bool.self) {
				array.append(value)
			} else if let value = try? decode(Int.self) {
				array.append(value)
			} else if let value = try? decode(Int8.self) {
				array.append(value)
			} else if let value = try? decode(Int16.self) {
				array.append(value)
			} else if let value = try? decode(Int32.self) {
				array.append(value)
			} else if let value = try? decode(Int64.self) {
				array.append(value)
			} else if let value = try? decode(UInt.self) {
				array.append(value)
			} else if let value = try? decode(UInt16.self) {
				array.append(value)
			} else if let value = try? decode(UInt32.self) {
				array.append(value)
			} else if let value = try? decode(UInt64.self) {
				array.append(value)
			} else if let value = try? decode(Float.self) {
				array.append(value)
			} else if let value = try? decode(Double.self) {
				array.append(value)
			} else if let value = try? decode(String.self) {
				array.append(value)
			} else if let nestedDictionary = try? decode(Dictionary<String, Any>.self) {
				array.append(nestedDictionary)
			} else if let nestedArray = try? decodeNestedArray(Array<Any>.self) {
				array.append(nestedArray)
			} else if let value = try? decodeNil(), value {
				array.append(NSNull()) //unavoidable, but should be fine. We return [Any]. An overload to return homegenous array would be nice.
			} else {
				//if the right type is not found, it will get stuck in an infinite loop, throw, we can't handle it
				throw EncodingError.invalidValue("<UNKNOWN TYPE>", EncodingError.Context(codingPath: codingPath, debugDescription: "<UNKNOWN TYPE>"))
			}
		}
		
		return array
	}
	
	mutating func decodeNestedArray(_ type: [Any].Type) throws -> [Any] {
		// throws: `CocoaError.coderTypeMismatch` if the encountered stored value is not an unkeyed container.
		var nestedContainer = try self.nestedUnkeyedContainer()
		return try nestedContainer.decode(Array<Any>.self)
	}

	mutating func decode(_ type: [String: Any].Type) throws -> [String: Any] {
		// throws: `CocoaError.coderTypeMismatch` if the encountered stored value is not a keyed container.
		let nestedContainer = try self.nestedContainer(keyedBy: JSONCodingKeys.self)
		return try nestedContainer.decode(type)
	}
}

extension KeyedEncodingContainerProtocol where Key == JSONCodingKeys {
	
	mutating func encode(_ value: [String: Any]) throws {
		for (key, value) in value {
			let key = JSONCodingKeys(stringValue: key)
			switch value {
			case let value as Bool:
				try encode(value, forKey: key)
			case let value as Int:
				try encode(value, forKey: key)
			case let value as Int8:
				try encode(value, forKey: key)
			case let value as Int16:
				try encode(value, forKey: key)
			case let value as Int32:
				try encode(value, forKey: key)
			case let value as Int64:
				try encode(value, forKey: key)
			case let value as UInt:
				try encode(value, forKey: key)
			case let value as UInt8:
				try encode(value, forKey: key)
			case let value as UInt16:
				try encode(value, forKey: key)
			case let value as UInt32:
				try encode(value, forKey: key)
			case let value as UInt64:
				try encode(value, forKey: key)
			case let value as Float:
				try encode(value, forKey: key)
			case let value as Double:
				try encode(value, forKey: key)
			case let value as String:
				try encode(value, forKey: key)
			case let value as [String: Any]:
				try encode(value, forKey: key)
			case let value as [Any]:
				try encode(value, forKey: key)
			case is NSNull:
				try encodeNil(forKey: key)
			case Optional<Any>.none:
				try encodeNil(forKey: key)
			default:
				throw EncodingError.invalidValue(value, EncodingError.Context(codingPath: codingPath + [key], debugDescription: "Invalid JSON value"))
			}
		}
	}
}

extension KeyedEncodingContainerProtocol {
	mutating func encode(_ value: [String: Any]?, forKey key: Key) throws {
		guard let value = value else { return }
		
		var container = nestedContainer(keyedBy: JSONCodingKeys.self, forKey: key)
		try container.encode(value)
	}
	
	mutating func encode(_ value: [Any]?, forKey key: Key) throws {
		guard let value = value else { return }
		
		var container = nestedUnkeyedContainer(forKey: key)
		try container.encode(value)
	}
}

extension UnkeyedEncodingContainer {
	
	mutating func encode(_ value: [Any]) throws {
		for (index, value) in value.enumerated() {
			switch value {
			case let value as Bool:
				try encode(value)
			case let value as Int:
				try encode(value)
			case let value as Int8:
				try encode(value)
			case let value as Int16:
				try encode(value)
			case let value as Int32:
				try encode(value)
			case let value as Int64:
				try encode(value)
			case let value as UInt:
				try encode(value)
			case let value as UInt8:
				try encode(value)
			case let value as UInt16:
				try encode(value)
			case let value as UInt32:
				try encode(value)
			case let value as UInt64:
				try encode(value)
			case let value as Float:
				try encode(value)
			case let value as Double:
				try encode(value)
			case let value as String:
				try encode(value)
			case let value as [String: Any]:
				try encode(value)
			case let value as [Any]:
				try encodeNestedArray(value)
			case is NSNull:
				try encodeNil()
			case Optional<Any>.none:
				try encodeNil()
			default:
				let keys = JSONCodingKeys(intValue: index).map({ [ $0 ] }) ?? []
				throw EncodingError.invalidValue(value, EncodingError.Context(codingPath: codingPath + keys, debugDescription: "Invalid JSON value"))
			}
		}
	}
	
	mutating func encode(_ value: [String: Any]) throws {
		var container = nestedContainer(keyedBy: JSONCodingKeys.self)
		try container.encode(value)
	}
	
	mutating func encodeNestedArray(_ value: [Any]) throws {
		var container = nestedUnkeyedContainer()
		try container.encode(value)
	}
}

This is great!
Only, this encodes Int value 0 as Bool. And if we change the order it encodes Bool value false as Int 0. How can this be fixed?
Thank you!

Not pretty, but checking for Bool this way before entering the switch solves the problem:

if value is Bool {
       let bval = value as! NSNumber
       if (bval === kCFBooleanTrue || bval === kCFBooleanFalse) {
                print("It's a Bool: \(key.stringValue), \(bval)")
                try encode(bval.boolValue, forKey: key)
       } else if value is Int {
               print("It's an Int: \(key.stringValue), \(value)")
               try encode(bval.intValue, forKey: key)
       }
} else {
    switch (value)

New gist here: https://gist.github.com/JBergsee/f349929f758d144e1b38d17e4cafb39d