Lateral

Basically a forEachAsync that allows n async calls at once.

Another way to think of it is as a thread pool for JavaScript.

Say you have 500 http requests that you want to get done 10 at a time in batches of 400, 50, and 50 and you want to know when each batch (and all batches) have finished... lateral is your guy!

Node.js Installation

Node.JS (Server):

npm install lateral

Browser Installation

You can install from bower:

bower install lateral

Or download the raw file from https://raw.github.com/FuturesJS/lateral/master/lateral.js:

wget https://raw.github.com/FuturesJS/lateral/master/lateral.js

Or build with pakmanager:

pakmanager build lateral

Usage

;(function () {
  'use strict';

  var Lateral = window.Lateral || require('lateral').Lateral
    , maxCallsAtOnce = 4 // default
    , lateral
    ;

  function onEach(complete, item, i) {
    setTimeout(function () {
      console.log(item);
      complete();
    }, 500);
  }

  lateral = Lateral.create(onEach, maxCallsAtOnce);

  lateral.add(['a', 'b', 'c', 'd']).then(function () {
    console.log('first batch done');
  });
  lateral.add(['d', 'e', 'f', 'g']).then(function () {
    console.log('second batch done');
  });
  
  lateral.then(function () {
    console.log('did all the things');
  });
}());

API

• lateral = Lateral.create(fn, n)
  • create a Lateral that will execute fn on each item to do at most n things at once
• lateral.add(arr).then(cb) - adds arr to be handled by fn and cb is called when all in arr are handled
• lateral.then(callback)
  • Fires callback when all items in added arrays have been handled

TODO

The code is a little hairy and could use some cleaning.