Do.this is a Swift 5 quick async helper inspired by node.js Async
Do.this { this in
//do stuff
this.succeeded(someResult)
}.then (name: "result step") { this in
//do more stuff
//every this has an index property and an optional name property
//which can be useful for debugging and error handling
print("this: \(this.name ?? String(this.index))")
//you can also access the previous result if needed:
print("previousResult: \(this.previousResult)")
//or just the previous value:
print("previousResult: \(this.previousValue)")
//if you're doing anything async, don't forget to call done()
DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
//async stuff
//btw, result value is optional
this.succeeded()
}
}.then (after: 2) { this in
//you can also add a delay directly
this.succeeded()
}.then { this in
//if an error happened the chain will break (see catch and finally below)
let error = SomeError.bummer
this.failed(error)
}.then (on: DispatchQueue.global(qos: .background)) { this in
//this will execute in a background queue
//(+you can combine this with a delay)
print("on: \(DispatchQueue.currentLabel)")
//and you can use swift Result objects
let result: Result<String, Error> = .success("cool!")
this.done(result)
}.then (on: .main) { this in
//this will be execute in the main queue
//if you dont specify a queue, this will be executed on the current (last used) queue
print("on: \(DispatchQueue.currentLabel)")
this.succeeded(someResult)
}.catch { this in
//catch an error, this will point to the step that triggered the error
print("catched error: \(this.error) from \(this.name ?? String(this.index))")
}.finally { this in
//finally - will execute even if an error happened
print("finally (previousResult: \(this.previousResult))")
exp.fulfill()
}Swift 5
Do.this is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod "Do.this"Barak Harel
Do.this is available under the MIT license. See the LICENSE file for more info.