Extending or adding functions to modules of Node

// module that you like to extend
var async = require('async')

// add a new function, myOwnFunction, to the module
async.myOwnFunction = function () {
  // do something
}

// re-export the module, for the changes to take effect
module.exports = async

The steps in order to complete this would be:

• Get the module's pre-defined functionality as your own variable
• Modify, delete, and/or append more functionality to the variable (via Javascript's functional paradigm)
• Re-export the variable as your own, which allows you to require it (either as an NPM module or as a file module).

First, we require async.

var newModule = require('async');

Now that we've retrieved the module async, we can append our own function.

newModule.betterParallel = function(myParameters) { ... };

Not only can we add our own function, but we can even delete from the module - since it is now our own.

delete newModule['series'];

With that completed, we need to then re-export our new module.

module.exports = newModule;

If you want to publish this to NPM as your own module, you can use npm publish. If you don't want to, you can simply require this file - and now it contains your modified changes.