A helper class to decode JSON data from a JSON file in the bundle or from a `Data` object instance. The class exposes two static functions that user can call without initializing the class.

JSONLoader.swift

//
//  JSONLoader.swift
//  Load JSON from file and data objects effortlessly
//
//  Created by Nick on 9/22/19.
//  Copyright © 2019 Nick. All rights reserved.
//

import Foundation

class JSONLoader: NSObject {
    
    static func loadJSON<T: Codable>(from file: String) -> T {
        
        // Get the file URL from the bundle
        guard let fileURL = Bundle.main.url(forResource: file, withExtension: nil) else { fatalError("File not found at given path") }
        
        // Do not worry about force cast, if it is empty, it will lead to a fala error below
        var data: Data!
        
        // Construct the data
        do {
            data = try Data(contentsOf: fileURL)
        }
        catch let ex {
            fatalError("Unable to get data from the JSON file: \(ex.localizedDescription)")
        }
        
        // Decode the JSON else die
        let decoder = JSONDecoder()
        do {
            return try decoder.decode(T.self, from: data)
        }
        catch let ex {
            fatalError("Unable to decode the JSON data: \(ex.localizedDescription)")
        }
    }
    
    static func decodeJSON<T: Codable>(from data: Data) -> T {
        
        let decoder = JSONDecoder()
        
        do {
            return try decoder.decode(T.self, from: data)
        }
        catch let ex {
            fatalError("Unable to decode from the JSON: \(ex.localizedDescription)")
        }
        
    }
    
}