What is the best control flow module for node.js?

Question

I've used caolan's async module which is very good, however tracking errors and the varying way of passing data through for control flow causes development to sometimes be very difficult.

I would like to know if there are any better options, or what is currently being used in production environments.

Thanks for reading.

Answer 1

I use async as well. To help tracking errors it's recommended you name your functions, instead of having loads of anonymous functions:

async.series([
  function doSomething() {...},
  function doSomethingElse() {...},
  function finish() {...}
]);

This way you'll get more helpful information in stack traces.

Answer 2

...however tracking errors and the varying way of passing data through for control flow causes development to sometimes be very difficult.

I've recently created a simple abstraction named "wait.for" to call async functions in sync mode (based on Fibers): https://github.com/luciotato/waitfor

Using wait.for, you can use 'try/catch' while still calling async functions, and you keep function scope (no closures needed). Example:

function inAFiber(param){
  try{
     var data= wait.for(fs.readFile,'someFile'); //async function
     var result = wait.for(doSomethingElse,data,param); //another async function
     otherFunction(result);
  }
  catch(e) {
     //here you catch if some of the "waited.for" 
     // async functions returned "err" in callback
     // or if otherFunction throws
};

see the examples at https://github.com/luciotato/waitfor

Answer 3

Sometimes it is hard to put all the functions in an array. When you have an array of objects and want to do something for each object, I use something like the example below.

read more in: http://coppieters.blogspot.be/2013/03/iterator-for-async-nodejs-operations.html

 var list = [1, 2, 3, 4, 5];
 var sum = 0;

 Application.each(list, function forEachNumber(done) { 
   sum += this; 

   // next statement most often called as callback in an async operation
   // file, network or database stuff

   done(); // pass an error if something went wrong and automatically end here

 }, function whenDone(err) { 
   if (err) 
     console.log("error: " + err);
   else
     console.log("sum = " + sum); 

});

I name the functions, because it is easier to debug (and easier to read)