Espresso

Espresso is a Swift convenience library for iOS.
Everything is better with a little coffee. ☕️

Installation

CocoaPods

use_frameworks!
pod 'Espresso', '~> 3.0'

Subspecs

Espresso is broken down into several subspecs making it quick & easy to pick and choose what you need. By default, the UIKit subspec is installed.

• Core: Core classes, extensions, & dependencies
• UI
  • UI-Core: General UI classes, extensions, & dependencies.
  • UI-UIKit: UIKit classes, extensions, & dependencies
  • UI-SwiftUI: SwiftUI classes, extensions, & dependencies
• PromiseKit: PromiseKit classes, extensions, & dependencies
• UIKit: Aggregate subspec that includes everything related to UIKit
• SwiftUI: Aggregate subspec that includes everything related to SwiftUI
• All: Aggregate subspec that includes everything

If you're unsure of what you want/need, we also some "recipe" subspecs that provide a good starting point with bundled Espresso classes & common third-party dependecies.

• Recipe-Modern-UIKit
  • Espresso/UI-UIKit
  • Espresso/PromiseKit
  • Spider-Web/All
  • Director/All
  • Swinject

Espresso

Espresso adds a bunch of useful features and extensions to components commonly used while developing for Apple platforms.

Some of the more interesting things include:

• UIAnimation classes with a promise-like chaining system
• UIViewControllerTransition system for easy custom UIViewController transitions
• AppleDevice identification & information
• MVVM base classes (i.e. ViewModel, UIViewModelView, UIViewModelViewController)
• Combine helper classes & extensions
• Crypto & digest hashing helpers
• User authentication (Face ID, Touch ID, Passcode) helpers
• + much more!

UIAnimation

Espresso includes a robust animation system built on top of UIViewPropertyAnimator. An animation is created with a timing curve, duration, delay, & animation closure.

let view = UIView()
view.alpha = 0

// Simple curve (default timing + default values)

UIAnimation {
    view.alpha = 1
}.start()

// Simple curve (default timing + custom values)

UIAnimation(duration: 0.5, delay: 0) {
    view.alpha = 1
}.start()

// Simple curve (custom)

UIAnimation(.simple(.easeOut), duration: 0.4) {
    view.alpha = 1
}.start()

// Spring curve

UIAnimation(.spring(damping: 0.9, velocity: 0.25)) {
    view.alpha = 1
}.start {
    print("The animation is done!")
}

The following timing curves are currently supported:

• simple
• cubicBezier
• spring
• defaultSpring
• material
• custom

UIAnimation also supports animation chaining. This let's you easily define a series of animations to run in succession (similar to a key-frame animation) using a promise-like syntax.

UIAnimation(duration: 0.3) {
    view.alpha = 1
}.then {
    view.backgroundColor = .red
}.start()

All parameters of a regular UIAnimation are available to you while chaining:

UIAnimation(duration: 0.3) {
    view.alpha = 1
}.then(.defaultSpring, duration: 0.4) {
    view.backgroundColor = UIColor.red
}.start()

Animations can be created and executed at a later time! Running your animations directly from an array without chaining is also supported.

let a1 = UIAnimation {
    view.alpha = 1
}

let a2 = UIAnimation(.simple(.easeIn), duration: 0.5) {
    view.backgroundColor = UIColor.red
}

[a1, a2].start {
    print("The animations are done!")
}

UIViewControllerTransition

Built on top of UIAnimation, Espresso's view controller transition system makes it easy to build beautiful custom transitions into your app. A simple UIViewControllerTransition implementation might look something like this:

class CustomFadeTransition: UIViewControllerTransition {

    public override func animations(using ctx: Context) -> UIAnimationGroupController {

        let sourceVC = ctx.sourceViewController
        let destinationVC = ctx.destinationViewController
        let container = ctx.containerView
        let context = ctx.context

        return UIAnimationGroupController(setup: {

            destinationVC.view.alpha = 0
            destinationVC.view.frame = context.finalFrame(for: destinationVC)
            container.addSubview(destinationVC.view)

        }, animations: {

            UIAnimation {
                destinationVC.view.alpha = 1
            }

        }, completion: {

            context.completeTransition(!context.transitionWasCancelled)

        })

    }

}

There's only one function that needs to be overridden from a transition subclass, animations(using:). This function provides you with contextual information about the transition, and expects you to return a UIAnimationGroupController containing setup, animation, & completion closures.

To present your view controller using a transition, set it's transition property before presentation. Helper functions on UIViewController & UINavigationController have also been added:

let transition = CustomFadeTransition()

present(
    viewController, 
    using: transition
)

navigationController.push(
    viewController, 
    using: transition
)

The following view controller transitions are included with Espresso:

• UIFadeTransition
• UISlideTransition
• UICoverTransition
• UIRevealTransition
• UISwapTransition
• UIPushBackTransition
• UIZoomTransition

User Authentication

The UserAuthenticator class helps with authenticating a user via Face ID, Touch ID, or a passcode. An appropriate authentication type will be chosen automatically (i.e. devices that support Face ID will prefer Face ID, devices with Touch ID will use Touch ID). If Face ID & Touch ID are unavailable, passcode authentication will be used.

UserAuthenticator.authenticate(withReason: "The app needs to authenticate you.") { (success, error) in
    print("Authenticated: \(success)")
}

NOTE: NSFaceIDUsageDescription key must be added to your Info.plist if you intend to authenticate via Face ID.

Digest Hashing

Hashing extensions are available on both Data & String:

let data = Data()
let hashedData = data.hashed(using: .md5)

let string = "Hello, world!"
let hashedString = string.hashed(using: .md5)

The following hash types are included with Espresso:

• md5
• sha1
• sha224
• sha256
• sha384
• sha512

Contributing

Pull-requests are more than welcome. Bug fix? Feature? Open a PR and we'll get it merged in! 🎉