WWDC19

Table of Contents

=================

• Introducing Combine and Advances in Foundation - Thursday
• Foundation Updates
  • Ordered Collection Diffing
  • Data
    • Contiguity
    • Compression
    • Units
    • Displaying a Date or Time
    • List Formatter
  • Operation Queue
    • Progress Reporting
• Swift Updates * Scanner * FileHandle
• Introducing Combine -> The replacement for Rx!
  • Publisher
  • Subscriber
  • Operator

Introducing Combine and Advances in Foundation - Thursday

Session materials: https://developer.apple.com/videos/play/wwdc2019/711/

Foundation Updates

Ordered Collection Diffing

let diff = bird.difference(from: bear)
let newBird = bear.applying(diff) // [b, i, r, d]

• Applicable to any collection type

Data

Contiguity

• struct Data becomes contiguous
  • public protocol ContiguousByte

Compression

let compressed = try data.compressed(using: BUILT_IN_COMPRESSION_ALGORITHM_ENUMS)

Units

• Added new UnitDurations & a new UnitFrequency
• UnitInformationStorage

Displaying a Date or Time

• Relative Date Time Formatter!!!!

List Formatter

let listFormatter = ListFormatter()
let dateFormatter = dateFormatter()

listFormatter.itemFormatter = dateFormatter
let string = listFormatter.string(from: dates)

Operation Queue

queue.addBarrierBlock {
  save()
}

• This guarantees that a given task is the only one running at a given particular time. Blocks the other remaining ones

Progress Reporting

let queue = OperationQueue()
queue.progressCount = SomeNumber

• Be prepared for UWSB and SMB on iOS to take multiple and disappearing volumes into account

Swift Updates

Scanner

• scanUpToCharacters(from:) & scanString()

FileHandle

• A new error-based API

• Use DataProtocol instead if [UIInt8]`
• Format dates and lists with Formatter
• Use OperationQueue s barrier and progress reporting

Introducing Combine -> The replacement for Rx!

• A unified declarative API for processing values over time
• Generic
• Type safe
• Composition first
• Request driven

Publisher

• Defines how values and error are produced
• One key function: “subscribe”
• Value type

Subscriber

• Reference type
• It can receive one subscription. N inputs and one completion

Operator

• Like a mapper between Publisher and Subscriber
• Adopts Publisher

• struct Map

• Ability to chain operators exactly like RxSwift
• Chaining results in a cancellable
• Combine adopts many known Rx patterns