chosa91

libdispatch efficiency tips

I suspect most developers are using the libdispatch inefficiently due to the way it was presented to us at the time it was introduced and for many years after that, and due to the confusing documentation and API. I realized this after reading the 'concurrency' discussion on the swift-evolution mailing-list, in particular the messages from Pierre Habouzit (who is the libdispatch maintainer at Apple) are quite enlightening (and you can also find many tweets from him on the subject).

• https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170828/date.html
• https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170904/date.html
• https://twitter.com/pedantcoder

My take-aways are:

chosa91

struct StateMachine<State, Action> {
  private(set) var state: State
  private let transition: (State, Action) -> State?

  init(startState: State, transition: @escaping (State, Action) -> State?) {
    self.state = startState
    self.transition = transition
  }

  mutating func apply(action: Action) -> Bool {

chosa91

@discardableResult
public func with<T>(_ value: T, _ builder: (T) -> Void) -> T {
    builder(value)
    return value
}

@discardableResult
public func with<T>(_ value: T, _ builder: (T) throws -> Void ) rethrows -> T {
    try builder(value)
    return value

chosa91

// Avoids the keyboard in a UIKit app by leveraging additionalSafeAreaInsets.
// You can put this in the root view controller so the whole app will avoid the keyboard.
// Only tested on iOS 13.3.
// Made for https://douglashill.co/reading-app/
@objc func updateSafeAreaForKeyboardFromNotification(_ notification: Notification) {
    guard let endFrameInScreenCoords = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
        return
    }

    // Please consider whether the force unwrap here is safe for your own use case.

chosa91

extension FileManager {
    /*
        Prints out the locations of the simulator and the shared group folder.
        This is useful for debugging file issues.

        Example usage: FileManager.default.printFileLocations()
     */
    func printFileLocations() {
        let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
        let simulatorFolder = paths.last!

chosa91

# A Best in Class Checklist
A boiled down checklist adapted from this [post](https://www.swiftjectivec.com/a-best-in-class-app/), created by @jordanmorgan10.

> To use this, create a Github Issue in your own repo, and simply copy and paste this text.

## iOS Core Technology
_Things any iOS app can benefit from_

- [ ] iCloud Sync
- [ ] [Core Spotlight integration](https://github.com/DreamingInBinary/Spend-Stack/issues/120)