Swift Functional Programming - Second Edition

Store

Then we want to store the list of Todo items in memory. To be able to achieve this, we will create a new class called TodoStore. The code is as follows:

import Vapor final class TodoStore {     static let sharedInstance = TodoStore()     fileprivate var list: [Todo] = Array<Todo>()     private init() {     } } 

For the sake of simplicity, we make this class a singleton that stores a list of Todo items. Also, we make the init method private to avoid non-shared instance initiation.

Next, we add the following methods:

func addOrUpdateItem(item: Todo) {     if self.find(id: item.todoId) != nil {         _ = update(item: item)     } else {         self.list.append(item)     } } func listItems() -> [Todo] {     return self.list } 

As the names suggest, these methods will be ...