NCCCoding

Small helpers that remove the boilerplate of reading and writing Codable values as JSON files.

• Encode any Encodable value to a file URL, or to a filename in a standard directory (Documents by default).
• Decode any Decodable value from a file URL or filename, as a Result or an optional.
• Writes are atomic.
• Optional NCCCodingCodable conformance adds encode(to:) / init?(from:) helpers directly on your types.

• iOS 12+ / macOS 10.15+
• Swift 5.2+

Add the package with Swift Package Manager:

dependencies: [
    .package(url: "https://github.com/drewster99/NCCCoding.git", from: "1.1.0")
]

Then add "NCCCoding" to your target's dependencies.

import Foundation
import NCCCoding

struct Settings: Codable {
    var username: String
    var volume: Double
}

let settings = Settings(username: "andrew", volume: 0.8)

// Write to Documents/settings.json
if let error = NCCCoding.encode(settings, filename: "settings.json") {
    print("Save failed: \(error.localizedDescription)")
}

// Read it back, keeping the error
let result: Result<Settings, Error> = NCCCoding.decode(filename: "settings.json")
switch result {
case .success(let loaded):
    print(loaded.username)
case .failure(let error):
    print("Load failed: \(error.localizedDescription)")
}

// Or read it back as an optional (nil on any failure)
let maybeSettings: Settings? = NCCCoding.decode(filename: "settings.json", in: .cachesDirectory)

// Explicit file URLs work too
let url = FileManager.default.temporaryDirectory.appendingPathComponent("settings.json")
let encodeError = NCCCoding.encode(settings, to: url)
let fromURL: Result<Settings, Error> = NCCCoding.decode(url)

struct Profile: Codable, NCCCodingCodable {
    var name: String
}

let profile = Profile(name: "Andrew")
let saveError = profile.encode(filename: "profile.json")   // Error? (nil on success)
let loaded = Profile(from: "profile.json")                 // Profile? (nil on any failure)

• Directories: filename-based APIs resolve the first matching directory in the user domain and create it if it does not exist. Filenames are appended as-is; no extension is added.
• Errors: Result and Error? APIs return the underlying EncodingError, DecodingError or Cocoa file error unchanged, except when the directory cannot be resolved, which returns NCCCoding.NCCCodingError.unableToFindSearchPathDirectory. The optional-returning APIs return nil for every failure, so use the Result APIs when you need to tell a missing file from corrupt data. Failures are also logged with os_log (error level, private).
• Dates: encoded and decoded as ISO 8601 strings. Encoding keeps whole seconds only, so fractional seconds are lost on a round trip.
• Non-finite floats: Double.infinity, -Double.infinity and Double.nan are stored as the strings "+Infinity", "-Infinity" and "NaN".

MIT. See LICENSE.