Passing data back from async in node.js

Question

Passing data back from async in node.js

I'm using async and trying to get data to pass back. Is this possible or do I need to use another library approach?

Ideally, I'd like to do something like:

async.forEach(txids, processTransaction, function(asyncErr, outputTotal) {

node.js
asynchronous

Answer 1

I think you want async.reduce(), similar to Array.reduce() but asynchronous.

The given example is:

async.reduce([1,2,3], 0, function(memo, item, callback){
    // pointless async:
    process.nextTick(function(){
        callback(null, memo + item)
    });
}, function(err, result){
    // result is now equal to the last value of memo, which is 6
});

You would probably do something similar to:

async.reduce(txids, {}, processTransaction, function(err, output) { });

I'm not sure what processTransaction returns, so I'm not sure what your memo (or initialValue) should be.