mitchtreece/broadcast

Lightweight instance syncing & property binding.

Objective-C support was dropped in version 2.0.0. If you need it, please use version 1.4.0 or lower.

Overview

Broadcast is a quick-and-dirty solution for instance syncing and property binding. Similar things can be achieved with libraries like ReactiveCocoa, but these are often overly-complicated and more robust than needed.

Installation

CocoaPods

Broadcast is integrated with CocoaPods!

1. Add the following to your Podfile:

use_frameworks!
pod 'Broadcast'

2. In your project directory, run pod install
3. Import the Broadcast module wherever you need it
4. Profit

Manually

You can also manually add the source files to your project.

1. Clone this git repo
2. Add all the Swift files in the Broadcast/ subdirectory to your project
3. Profit

Broadcastable

The Broadcastable protocol defines an object that can notify and react when property changes occur. To conform to Broadcastable, an object simply needs to return a broadcast identifier, and call broadcast.make() when initialized. This broadcast identifier will be used to identify matching instances and notify them of changes.

class Post: Broadcastable {

    var postId: String
    var numberOfLikes: Int

    var broadcastId: String {
        return postId
    }

    init(postId: String, numberOfLikes: Int) {

        self.postId = postId
        self.numberOfLikes = numberOfLikes
        self.broadcast.make()

    }

}

Signaling

Any changes made inside a signal block will be propagated to all instances of an object that share the same identifier. The signal() function's closure provides a "proxy" template object that will be swapped with the actual matching concrete Broadcastable object upon execution.

post.broadcast.signal { (aPost) in
    aPost.numberOfLikes += 1
}

Listening

Broadcastable objects can be externally observed for changes. This is extremely useful when you need to bind your UI to an object's properties.

class PostCell: UITableViewCell {

    var listener: BroadcastListener?

    var post: Post? {
        didSet {

            guard let post = post else { return }

            layoutUI(with: post)

            listener = post.broadcast.listen { [weak self] in
                self?.layoutUI(with: post)
            }

        }
    }

    ...

}

Groups of Broadcastable objects can also be observed at once via BroadcastGroupListener:

var listener: BroadcastGroupListener?

let posts = [
    Post(postId: "0", numberOfLikes: 3),
    Post(postId: "1", numberOfLikes: 13),
    Post(postId: "2", numberOfLikes: 23)
]

listener = posts.listen { (object) in
    print("A post was updated!")
}

broadcast's Issues

makeBroadcastable should not be part of the protocol

Since users should not implement it