Are there any ways to make several signals into one signal instead of flatten them in Reactive Cocoa

Question

First. Let me introduce the background of this question. I have several network requests to send.

(RA means Request A, and -----> means the result of the previous request will be sent to the next request)

• RA---->RB---->RC
• RD
• RE---->RF

Here are 3 bundles of requests. Now I want to subscribe the signal that any of the bundles that has the response.

Since every request can be represented as a signal e.g SA, so the signal flow should look like:

• SA---->SB----->SC
• SD
• SE---->SF

Then are there any signals in the Reactive Cocoa to handle this?

What I do now is to flatten map them

Signal* bundleOne = [[[SA flatternMap:(^RACStream *(NSString* resultOfA) {
                         return SB;
                    }] flatternMap:(^RACStream *(NSString* resultOfB) {
                         return SC;
                    ];

 Signal* bundleTwo = SD;

 Signal* bundleThree = [[[SE flatternMap:(^RACStream *(NSString* resultOfE) {
                         return SF;
                       }]; 

The next step would be that how to create a signal when any of the bundleOne, bundleTwo, bundleThree signals has result.

I have tried

[[RACSignal merge: @[bundleOne, bundleTwo, bundleThree]] any] subscribeNext:
          ^(id object) {xxx}];

But failed. Because the bundle signal is made up of the flattened signals, and from the implementation of the any, it also flattens the signal. So that SA, SB, SC, SD, SE, SF are all flattened and when SA returns, the any signal returns. This is not what I want. (I want that SA--->SB--->SC, the final SC returns, the bundleOne returns)

Could any one help me? or Reactive Cocoa doesn't fit for this? I have to resort to the nested block again....

Thanks a lot.

Answer 1

Try the zip: operator. I am not sure if I completely understand what you want to do but I think zip might do the trick.

see the zip docs