Weakable

Weakable is an easy way to hold weak references in Swift.

With Weakable you can create weak arrays, weak dictionaries and many other cool things.

😎

Requirements

• iOS 12+
• watchOS 4+
• tvOS 12+
• macOS 11+
• Swift 4+

Usage

Declare your Weak variable in one of the two ways provided:

//Given a class
class TestClass {}
//and an instance of that class
var aTestObject = TestClass()
//You can create a Weak like this:
var weakTestObject = Weak(aTestObject)
//Or using the shorthand operator ≈
var anotherWeakTestObject = ≈test

Access your variable:

weakTestObject.object //returns your value as an optional, since it may or may not have been released

Operators

Weakable comes with 3 operators, all using the ≈ character (⌥ + x).

• prefix ≈
  • Shorthand contructor for a Weak variable:

//Given an object
let object = AwesomeClass()
//you can create a Weak by either
var weakObject = Weak(object)
//or
var weakObject = ≈object

• postfix operator ≈
  • Shorthand accessor for Weak:

//Given a Weak
var weakObject = ≈object
//you can access the underlying object by
weakObject.object
//or
weakObject≈

• infix operator ≈
  • Shorthand assignment for Weak:

//Given a Weak
var weakObject = ≈object
//you can change the underlying object by
weakObject.object = anotherObject
//or
weakObject ≈ anotherObject

Arrays and Dictionaries

You can safely store your Weak variables in collections (eg. [Weak<TestClass>]). The underlaying objects won’t be retained.

var tests = (1...10).map { TestClass() } // 10 elements
var weakTests = ≈tests // 10 elements
tests.removeLast() // `tests` now have 9 elements, but `weakTests` have 10
weakTests = weakTests.filterWeaks() // `weakTests` now have 9 elements too, since we dropped the released objects from it

You can also quickly “unwrap” the elements in a Weak collection:

let tests = weakTests.compactWeaks()

The variable tests will now be a [TestClass] containing only the elements that haven’t been released yet.

Global weaks

Version 2.0 introduces the concept of global weak variables. Say you want to share the same instance of a class in several places, but you want to release the global variable once all other references are destroyed. That’s what a global weak is.

final class TestClass: WeaklyGloballyIdentifiable {
    typealias GlobalID = Int
    @WeakGlobalActor
    static var weakGlobals: [GlobalID: Weak<TestClass>] = [:]
}
let firstInstance = TestClass.weakGlobal(id: 1, default: TestClass())
let secondInstance = TestClass.weakGlobal(id: 1, default: TestClass())
print(firstInstance === secondInstance) // `true`

Installation

Swift Package Manager

dependencies: [
    .package(url: "https://github.com/BellAppLab/Weakable", from: "2.0")
]

Then import Weakable where needed.

Legacy

The following import methods only work for version 1.0.1.

Cocoapods

pod 'Weakable', '~> 1.0'

Then import Weakable where needed.

Carthage

github "BellAppLab/Weakable" ~> 1.0

Then import Weakable where needed.

Git Submodules

cd toYourProjectsFolder
git submodule add -b submodule --name Weakable https://github.com/BellAppLab/Weakable.git

Then drag the Weakable folder into your Xcode project.

Author

Bell App Lab, apps@bellapplab.com

Credits

Logo image by Артур Абт from The Noun Project

License

Weakable is available under the MIT license. See the LICENSE file for more info.