async-next

Async callback manager. Use async.now to run a set of functions in parallel or async.next to run in series.

Install

npm install async-next

Series Example

var Async = require('async-next');
var async = new Async();

async.next(function (next) {
    var count = 0;
    console.log('doing step 1');
    count++;
    next({value: "new value"}, count);
});

async.next(function (next, paramsFromFirstAsyncNext, count) {
    console.log('doing step 2');
    console.log('using passed params: ' + paramsFromFirstAsyncNext.value + " count: " + count);
    next();
});

async.next.start(function () {
  console.log('All done.');
});

Async Example

var async = new Async();
var path = require('path'), fs = require('fs');
var filesToUpdate = [], i;

//build file array to use as test update
for (i=0; i < 3; i++) {
    filesToUpdate.push({path: path.join(__dirname,'./files/file' + i + 'txt'), text: 'New Test Data for file: ' + i})
}

//now run async update
for (i=0; i < filesToUpdate.length; i++){
    async.now(function (next, file) {
        fs.writeFile(file.path,file.text, function(){
            console.log('done updating file: ' + file.path);
            next();
        });
    }, filesToUpdate[i]);
}

async.now.start(function(){
    console.log('Done with Async');
});

Combined async.next and async.now with nesting

var async = new Async();

async.next(function series1 (next){

    //starting a nested async.next will require all nested async calls to complete before the outer async.next will continue;
    async.next(function series1Nested1(next){
        console.log('done with series1Nested1');
        next();
    });

    async.next(function series1Nested2(next){
        console.log('done with series1Nested2');
        next();
    });
      async.next(function series1Nested3(next){
        console.log('done with series1Nested3');

        //calling next() on the last nested async.next will resume the outer async.next
        next();
    });

    //all nested async.next or async.now calls are started on nextTick.  That means their parent function will complete before they start.
    console.log('done with series1');
    //calling the outer async.next after adding nested async.next calls will start them - the outer async.next will continue after the last nested async.next has been called.
    next();
});//end async.next series1

async.next(function series2 (next){
    var path = require('path'), fs = require('fs');
    var filesToUpdate = [], i;

    //build file array to use as test update
    for (i=0; i < 3; i++) {
        filesToUpdate.push({path: path.join(__dirname,'./files/file' + i + 'txt'), text: 'New Test Data for file: ' + i})
    }

    //now run async update
    for (i=0; i < filesToUpdate.length; i++){
        async.now(function (next, file) {
            fs.writeFile(file.path,file.text, function(){
                console.log('done updating file: ' + file.path);
                next();
            });
        }, filesToUpdate[i]);
    }

    async.now.start(function(){
        console.log('done with nested async.now');

        //we need to call the outer next callback for the series2 function to continue our outer async.next series.
        next();
    });

    //all nested async.next or async.now calls are started on nextTick.  That means their parent function will complete before they start.
    console.log('done with series2');
});//end async.next series2

async.next(function series3 (next){
    console.log('done with series3');
    next();
});//end async.next series3

async.next.start(function(){
    console.log('all done with combined example.\n\n');
});

License

MIT