Closures
A Swift framework that adds closure handlers to UIKit and Foundation classes, replacing delegation and target-action patterns.
What is Closures?
Closures is a Swift framework that adds closure-based handlers to UIKit and Foundation classes, providing an alternative to traditional iOS design patterns like delegation and target-action. It allows developers to write more concise and functional code for handling user interactions, populating views, and managing control events. The framework is designed to be type-safe and scalable, avoiding Objective-C runtime tricks.
iOS developers who prefer functional programming styles or want to reduce boilerplate code when working with UIKit and Foundation APIs. It's particularly useful for those building iOS apps with Swift and looking for more expressive alternatives to delegation.
Developers choose Closures because it offers a Swifty, type-safe way to replace verbose delegation and target-action patterns with clean closure syntax. Its flexibility allows mixing traditional methods with closure handlers, and its daisy-chaining feature makes code organization intuitive.
Overview
Swifty closures for UIKit and Foundation
Use Cases
Best For
- Replacing UIControl target-action patterns with closure handlers
- Simplifying UITableView and UICollectionView data source implementation
- Adding gesture recognizers with concise closure syntax
- Organizing UITextField delegate methods using daisy chaining
- Handling UIImagePickerController media selection with closures
- Writing functional-style iOS code without Objective-C runtime dependencies
Not Ideal For
- Projects with strict no-third-party-dependency policies for security or compliance reasons
- Teams maintaining large Objective-C codebases where Swift closure integration adds complexity
- Applications primarily built with SwiftUI, as Closures is focused on UIKit and Foundation classes
Pros & Cons
Pros
Replaces verbose target-action and delegation with simple closures, as shown with button.onTap and tableView.addElements, significantly reducing boilerplate code.
Daisy chaining allows grouping related delegate methods, such as for UITextField, making code more readable and maintainable without scattering logic.
Supports mixing closure handlers with traditional delegate methods, as demonstrated with UITableView, allowing incremental adoption without a full rewrite.
Cons
As a specialized framework, it has a smaller community and fewer resources compared to mainstream libraries, which can slow down support and issue resolution.
The project's goal to become irrelevant if Apple adopts similar APIs means long-term maintenance is uncertain, risking obsolescence with iOS updates.
Extensive use of closures can lead to memory management issues like retain cycles if not carefully handled, requiring extra attention to [weak self] in examples.
Open Source Alternative To
Closures is an open-source alternative to the following products:
Frequently Asked Questions
Related Projects
SwifterSwiftA handy collection of more than 500 native Swift extensions to boost your productivity.
R.swiftStrong typed, autocompleted resources like images, fonts and segues in Swift projects
BlocksKitThe Objective-C block utilities you always wish you had.
PeripheryA tool to identify unused code in Swift projects.
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