Atom: A Swift repository from alexeuler

##Getting started

Installation

Atom is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "Atom"

Defining core classes

Event class

Define and enum, containing all possible events with parameters, e.g.

enum Event: AtomEvent {
    case AddTodo(name: String)   
    case ToggleTodo(key: Int)  
}

States

For each state implement AtomState protocol - define parentClass and impelement react and initial functions, e.g.

      struct Todo: AtomState {
          var name: String
          var checked: Bool
          
          typealias EventType = Event
          
          static var parentClass: AtomNode.Type = App.self
          
          static func react(optionalCurrent: Todo?, event: EventType) -> Todo {
              guard var current = optionalCurrent else { return initial() }
              
              switch event {
              case .ToggleTodo:
                  current.checked = !current.checked
              default:
                  break
              }
              
              return current
          }
          
          static func initial() -> Todo {
              return Todo(name: "", checked: false)
          }
      }

Root state

In addition to AtomState methods, Root State implement AtomRoot protocol, i.e. must hold a static instance of itself, e.g.:

    struct App: AtomState, AtomRoot {
        typealias EventType = Event
        static var instance = App.initial()
        static var parentClass: AtomNode.Type = App.self
        
        var todos: [Todo]
        
        static func react(optionalCurrent: App?, event: Event) -> App {
            guard var current = optionalCurrent else { return App.initial() }
            switch event {
            case .AddTodo(let name):
                let todo = Todo(name: name, checked: false)
                current.todos.append(todo)
                return current
            case .ToggleTodo(let key):
                current.todos[key] = Todo.react(current.todos[key], event: .ToggleTodo(key: key))
                return current
            }
        }
        
        static func initial() -> App {
            return App(todos: [])
        }
        
    }

Atom class

Define global Atom class implementing AtomProtocol and use it to dispatch events:

  class Atom: AtomProtocol {
      typealias RootType = State.App
  }

Now you can use Atom class to dispatch events, e.g. Atom.dispatch(Event.AddTodo(name: titleTextField.text ?? ""))

##Todo

Add logging as a middleware
Add time machine screen (i.e. view controller with all states history and ability to rollback states)
Add router
Add props change strategies

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

Description

State

State is the minimal required data to reconstruct the whole state of the app. State is constructed to be as close to view model as possible

Event

Event is the simple change of state

Action

Action emits one or more events. Every state change is made by actions

Props

Props are the viewmodel required to render a view (including that of viewcontroller)

Transformers

Transform state into props. The simpiest transformer just selects a part of the state relevant for the current view.

Author

Alexey Karasev, karasev.alexey@gmail.com

License

Atom is available under the MIT license. See the LICENSE file for more info.

alexeuler/Atom