Espresso

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

Installation

SPM

The easiest way to get started is by installing via Xcode. Just add Espresso as a Swift package & choose the modules you want.

If you're adding Espresso as a dependency of your own Swift package, just add a package entry to your dependencies.

.package(
    name: "Espresso",
    url: "https://github.com/mitchtreece/Espresso",
    .upToNextMajor(from: .init(3, 0, 0))
)

Espresso is broken down into several modules making it quick & easy to pick and choose exactly what you need.

• Espresso: Core classes, extensions, & dependencies
• EspressoUI: UIKit & SwiftUI classes, extension, & dependencies
• EspressoPromise: PromiseKit classes, extensions, & dependencies

CocoaPods

As of Espresso 3.1.0, CocoaPods support has been dropped in favor of SPM. If you're depending on an Espresso version prior to 3.1.0, you can still integrate using CocoaPods.

pod 'Espresso', '~> 3.1.0'

Usage

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! 🎉