DecodingJSONFromBundle.swift

// Decoding JSON from bundle

extension Bundle {
    func decode<T: Decodable>(_ type: T.Type, from filename: String) -> T {
        guard let json = url(forResource: filename, withExtension: nil) else {
            fatalError("Failed to locate \(filename) in app bundle.")
        }
        
        guard let jsonData = try? Data(contentsOf: json) else {
            fatalError("Failed to load \(filename) from app bundle.")
        }
        
        let decoder = JSONDecoder()
        
        guard let result = try? decoder.decode(T.self, from: jsonData) else {
            fatalError("Failed to decode \(filename) from app bundle.")
        }
        
        return result
    }
}

let items = Bundle.main.decode([ResponseItem].self, from: "Response.json")