flow

Simple & basic flow control with no dependencies. Its simple, fast. No BS. Its an extension of fastsync https://github.com/joekarl/fastsync.

Use it in browsify, webpack, node.js/io.js

Covers 4 basic use cases:

• parallel - Run functions in parallel and callback when finished
• series - Run functions in series and callback when finished
• waterfall - Run functions in series while passing results of one function to the next
• asyncMap - Convenience method for mapping an array using asynchronous functions, analogous to an async version of Array.forEach with all tasks kicked off in parallel
• seriesMap - Convenience method for mapping an array using asynchronous functions, analogous to an async version of Array.forEach with all tasks kicked off in series

##Note about function resolution All functions are resolved immediately, to delay/overhead of next tick of the event loop. If you need to evaluate on next tick, use either setImmediate or process.nextTick. Add a wrapper, probably on your functions.

Usage

$ npm install kevbook.flow --save
var flow = require('kevbook.flow');

##Examples ####parallel

flow.parallel([
  function one(cb) {
    setTimeout(function(){
        cb(null, 1);
    }, 100);
  },
  function two(cb) {
    setTimeout(function(){
        cb(null, 2);
    }, 100);
  },
  function three(cb) {
    setTimeout(function(){
        cb(null, 3);
    }, 100);
  },
  function four(cb) {
    setTimeout(function(){
        cb(null, 4);
    }, 100);
  }
], function(err, results){
  //100ms later
  console.log(results); //[1, 2, 3, 4]
});

####series

flow.series([
  function one(cb) {
    setTimeout(function(){
        cb(null, 1);
    }, 100);
  },
  function two(cb) {
    setTimeout(function(){
        cb(null, 2);
    }, 100);
  },
  function three(cb) {
    setTimeout(function(){
        cb(null, 3);
    }, 100);
  },
  function four(cb) {
    setTimeout(function(){
        cb(null, 4);
    }, 100);
  }
], function(err, results){
  //400ms later
  console.log(results); //[1, 2, 3, 4]
});

####waterfall

flow.waterfall([
  function(cb) {
    cb(null, 8);
  },
  function split(v, cb) {
    //v = 8
    cb(null, v / 2, v / 2);
  },
  function square(v1, v2, cb) {
    //v1 = 4, v2 = 4
    cb(null, v1 * v2);
  },
  function minus1(v, cb) {
    //v = 16
    cb(null, v - 1);
  }
], function(err, result){
  console.log(result); //15
});

####parallelMap Note Results can be processed in any order but will be returned in the order submitted

flow.parallelMap([1,2,3], function mult5(v, cb){
  setTimeout(function(){
    cb(null, v * 5);
  }, 100);
}, function(err, mappedArray){
  console.log(mappedArray); //[5,10,15]
});

####seriesMap

flow.seriesMap([1,2,3], function mult5(v, cb){
    setTimeout(function(){
        cb(null, v * 5);
    }, 100);
}, function(err, mappedArray){
    console.log(mappedArray); //[5,10,15]
});