async-each
No-bullshit, ultra-simple, 35-lines-of-code async parallel forEach function for JavaScript.
We don't need junky 30K async libs. Really.
For browsers and node.js.
Installation
- Just include async-each before your scripts.
 - 
npm install async-eachif you’re using node.js. - 
bower install async-eachif you’re using Bower. 
Usage
- 
each(array, iterator, callback);—Array,Function,(optional) Function - 
iterator(item, next)receives current item and a callback that will mark the item as done.nextcallback receives optionalerror, transformedItemarguments. - 
callback(error, transformedArray)optionally receives first error and transformed resultArray. 
Node.js:
var each = require('async-each');
each(['a.js', 'b.js', 'c.js'], fs.readFile, function(error, contents) {
  if (error) console.error(error);
  console.log('Contents for a, b and c:', contents);
});
Browser:
window.asyncEach(list, fn, callback);