andymatuschak

//
//  CollectionViewDataSource.swift
//  Khan Academy
//
//  Created by Andy Matuschak on 10/14/14.
//  Copyright (c) 2014 Khan Academy. All rights reserved.
//

import UIKit

jspahrsummers

MVVM example

For a command that initiates a network request when:

• The network connection is up (precondition)
• The network request is not already in progress (enforced serialization)

The lifecycle proceeds as follows:

1. The view model exposes the command and describes its behavior