fn to return extra arguments

[boneskull]

I looked through the codebase but didn't see this; sorry if I missed it.

Given the following function, I frequently find myself taking arguments[1..n] and doing something with it:

function foo(bar) {
  // do something with arguments[1..n]
}

So, a function like the following is helpful for me:

function extraArgs(fn, arg_obj) {
  var idx;
  arg_obj = arg_obj || [];
  if (!_.isFunction(fn)) {
    throw new Error('extraArgs() expects a function parameter');
  }
  idx = fn.toString()
    .replace(/^function\s+.*\((.+?)\).+/, '$1')
    .match(/\s*,\s*/)
    .length;
  return _.toArray(arg_obj).slice(idx);
}

Non-trivial example:

function formatError() {
  var message = require('util').format.apply(null, arguments);
  return new Error(message);
}

function httpError(status_code) {
  var e = formatError.apply(null, extraArgs(httpError, arguments));
  e.status_code = status_code;
  return e;
}

function frobulate(widget) {
  if (!_.isArray(widget)) {
    throw httpError(500, 'could not frobulate %s', widget);
  }
  // proceed to frobulate
}

frobulate({});

Would something like this be appropriate for this library? I can provide PR if there's interest.