Looking for a way to not exit on async.parallel on error.

[reggi]

Majority of my most recent use-cases involve async functions that aren't dependent on each other, and so when some async function breaks up top, the rest of my code doesn't execute. Wondering if there's a simple way to do something like this without being so obtrusive to the library / so much overhead. In this case I'd like to return false on error, so I'm building an object with every property intact, if something fails everything is else is still there, and false takes the broken async functions place.

var noError = function(func) {
  return function(callback) {
    func(function(err, value) {
      if (err) return callback(null, false);
      return callback(null, value);
    });
  }
}

var parallelNoError = function(functions, callback) {
  var newFunctions = {};
  for (var func in functions) {
    newFunctions[func] = noError(functions[func]);
  }
  return async.parallel(newFunctions, callback);
}

@aearly Would love your thoughts on this one too.

[reggi]

We can call it Surge to stick with the electrical theme?

[reggi]

Or perhaps a different route.

Instead of a whole new function, we could just wrap the individual functions in a async.surge, which will return something else on error.

async.surge(async.apply(fs.write, "file.txt"))

or

async.applySurge(fs.write, "file.txt")

[aearly]

There's a whole bunch of async combinators you could write to more easily plug functions together. I like this one, for when you don't care about the error. Another one would be to make async functions plug into the async.filter and async.reject family -- only callback a boolean, and false if there's an error.

[aearly]

Also, not sure about "surge" -- the theme isn't really electrical. async.parallel([ignoreError(fn)], calllback) something like ignoreError(fn) or withoutError(fn) or noError(fn).

[reggi]

Good feed back, thanks @aearly.

You don't think this should be included with async?

[aearly]

I'd wait to see what other think. There's a lot of stuff that could go in the grab-bag that is async.

[prasad83]

Having this as part of async would be great.
It would be nice to collect the errors like the results of each task in the parallel callback.

[aearly]

I'm putting together a collection of auxilliary higher-order async helper functions: acomb. A function like this would be welcome if you want to make a PR. :)

[reggi]

@aearly Took a look at acomb, really neat!

[goloroden]

+1, would love to see an option to continue on errors, too (although I don't need it for parallel, but for forEach).

[danielshir]

+1 for continuing on errors.
I have encountered a case where some functions running in parallel() will require cleanup code to run after completion. The current design scheme makes it hard to do so if an error occurs.

[colinmegill]

+1

[oillescas]

+1

[skilledDeveloper]

+1

[fizerkhan]

+1

[levino]

+1

[jvillanti]

+1

[aearly]

Closing this in favor of #942 . There's also the PR: #1012