CODEWITHSUNDEEP
xcodeswiftpromisekit
rclark
rclark

Reputation: 301

PromiseKit branching promise

Suppose you have a branch in your promise chain that could either return nothing or an AnyObject promise. What would you specify as the return type of the 'then' closure? For example:

func sample() -> Promise<AnyObject> {
    return Promise { fulfill, reject in
        fulfill(1)
    }
    .then { _ -> Void in
        if false {
            return Promise { fulfill, reject in
                fulfill(0)
            }
        }
    }
}

If I put Void as the return type for the 'then' closure I get a seg fault; if I put Promise as return type then I get an error:

missing return in a closure expected to return Promise<AnyObject>

Any suggestions?

Thanks

Upvotes: 0

Views: 573

Answers (1)

Daniel T.
Daniel T.

Reputation: 33977

Based on the code sample, I see no reason to return an AnyObject. If you want to optionally return Void or an Object, then make a promise that contains an optional.

func sample() -> Promise<AnyObject?> {
    return Promise { fulfill, reject in
        functionForGettingObjectWithCallback() { result: AnyObject? in
            fulfill(result)
        }
    }
}

Upvotes: 1

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