save array of struct to UserDefaults

UserDefaultsAndStructArray.swift

import Foundation

struct Book: Codable {
    let title: String
    let author: String
}

let KeyForUserDefaults = "myKey"

func save(_ books: [Book]) {
    let data = books.map { try? JSONEncoder().encode($0) }
    UserDefaults.standard.set(data, forKey: KeyForUserDefaults)
}

func load() -> [Book] {
    guard let encodedData = UserDefaults.standard.array(forKey: KeyForUserDefaults) as? [Data] else {
        return []
    }

    return encodedData.map { try! JSONDecoder().decode(Book.self, from: $0) }
}

save([Book(title: "The Great Gatsby", author: "Fitzgerald"),
      Book(title: "Ulysses", author: "Joyce")])

let books = load()
print(books) //[Book(title: "The Great Gatsby", author: "Fitzgerald"), Book(title: "Ulysses", author: "Joyce")]