SwiftyPromise

A simple promise framework for Swift.

This small library implements thread safe promises for Swift. It allows to create promises and fulfill or reject them asynchronously. Promises can be chained using the then method. Furthermore it has support for cancelling a promise chain.

Usage

let promise: Promise<String> = Promise { (_, fulfill, reject) in
    performSomeAsynchronousTaskWithCompletion() { (resultString: String?, error: ErrorType?) in
        if let string = resultString {
            fulfill(string)
        }
        else {
            reject(error)
        }
    }
}

promise.success { string in
    print("The result is: \(string)")
}.failure { error in
    print("Something went wrong: \(error)")
}

promise.then { (string) -> AnyObject in
    guard let data = string.dataUsingEncoding(NSUTF8StringEncoding) else {
        throw PromiseError.Generic
    }
    return try NSJSONSerialization.JSONObjectWithData(data, options: [])
}.success { (jsonObject) in
    print("Parsed json object: \(jsonObject)")
}.failure { error in
    print("Could not parse json: \(error)")
}

Installation

Using CocoaPods:

use_frameworks!
pod 'SwiftyPromise'

Using Carthage:

github "sroebert/SwiftyPromise"

Manually:

1. Drag SwiftyPromise.xcodeproj to your project in the Project Navigator.
2. Select your project and then your app target. Open the Build Phases panel.
3. Expand the Target Dependencies group, and add SwiftyPromise.framework.
4. Click on the + button at the top left of the panel and select New Copy Files Phase. Set Destination to Frameworks, and add SwiftyPromise.framework.
5. import SwiftyPromise whenever you want to use SwiftyPromise.

Requirements

• iOS 8.0+, Mac OS X 10.9+, tvOS 9.0+ or watchOS 2.0+
• Swift 3.0

Author

Steven Roebert (@sroebert)

License

SwiftyPromise is available under the MIT license.