Let's take a look at this code:

var mainFunction = function() {

  altFunction.apply(null, arguments);

}

The arguments that are passed to mainFunction are dynamic -- they can be 4 or 10, doesn't matter. However, I have to pass them through to altFunction AND I have to add an EXTRA argument to the argument list.

I have tried this:

var mainFunction = function() {

  var mainArguments = arguments;

  mainArguments[mainArguments.length] = 'extra data'; // not +1 since length returns "human" count.



  altFunction.apply(null, mainArguments);

}

But that does not seem to work. How can I do this?