An organizing of asynchronous code in javascript / c# ...

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Asynchronous codes in program aren't uncommon. It, however, from time to time, cause confusions in tracking and debugging codes that surrounding them. For example, programmer may forgot that an asynchronous task have been kicked off and that certain operations or functions would not and could not be performed until the task is done. To help with this end, there is this idea of keeping the kick off and call back functions close to each other. An example of this will be the Microsoft C# async and await keyword pair. Javascript mostly using the anonymous function to keep the kick off and the call back function closer.

An scenario I run into is that a single button click triggers several asynchronous tasks and the logic is required to monitor the result of each asynchronous task in order to react. As we can see, in this case, even though keeping call backs with triggers is good, keeping all call backs close to each other is also beneficial.

My solution to the situation is to pass in a gathering function to each trigger/call-back pair and has each call-back eventually call the gathering function. In this way, with logic in the gathering function, we can monitor all the result in one central place and helps debugging codes too. If desired, it is also possible to move all call back logic in the gathering function for centralized logic checking and debugging.

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