parallelize

control flow library for parallel async functions; it invokes the callback with the aggregated results or an error

example

Specify callback to run after all functions have completed at the end:

var parallelize = require('parallelize');

var next = parallelize();

fs.readFile(file1, next());
fs.readFile(file2, next());

next(function displayResults(err, results) {
  if (err) { throw err; }

  // `results` array with data in the order which the async fns were called
  console.log(file1 + ' contents', results[0]);
  console.log(file2 + ' contents', results[1]);
});

If you'd prefer to have a results object instead of an array check the results-object.js example for more details.

motivation

I wanted something similar to after that aggregates results. Note that I did not want to pass an array of functions like async does. There might be other libraries with similar approaches in the NPM registry, but nevertheless it was fun to create this one.

how it works

The function returned by the module should wrap all your callbacks. It has two roles:

• increase the internal parallel functions counter (to know how many functions there are)
• replaces your callbacks with a custom callback that decreases the counter until it reaches 0 or there's an error
• remembers the results of the async callbacks into order; if the callback is invoked with multiple arguments it puts those into an array

install

With npm do:

npm install parallelize

test

With npm do:

npm test

license

MIT