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A small library that lets you inject some code between a third party library and the execution context. With Middleman.js you can easily:

  • filter arguments passed to an original method,
  • pass one function's arguments to another function, or
  • overload a third party method to change how it works



Let's say you add a third party library to your application that has a method called doSomethingCool.

    var ThirdPartyLibrary = {
        doSomethingCool : function(firstParam, isAwesome) {
            // do something cool with firstParam, then: 
            if (isAwesome){
                console.log('All up in your app, doing awesome things.');

You decide that you want to force the second parameter isAwesome to be true every time doSomethingCool is called because your application is totally awesome. You could just write a wrapper method like this:

    var AwesomeApplication = {
        doSomethingCool : function(firstParam) {
            return ThirdPartyLibrary.doSomethingCool(firstParam, true);
    AwesomeApplication.doSomethingCool('blah blah blah');
     * console: All up in your app, doing awesome things.

However, now you have to remember to call your method instead of the original method. What if ThirdPartyLibrary is very popular (e.g. jQuery)? Your colleague Tony has been using ThirdPartyLibrary for years. He doesn't remember to use your wrapper function when writing new code for your application.

Middlman.js gets between Tony and ThirdPartyLibrary, so your application stays awesome. 😑

    var MM = new Middleman();{
        lib : ThirdPartyLibrary,
        method : 'doSomethingCool',
        filter : function(args) {
            // make the second parameter true 
            args[1] = true;
            return args;
    ThirdPartyLibrary.doSomethingCool("I'm Tony, and the second param is undefined.");
     * console: All up in your app, doing awesome things.

Piece of cake.