For when you're stuck in the middle

function.bindMap.js

Function.prototype.bindMap = function(context) {
  function nullfilter(v) { return v != null; }
  function isnotfalse(v) { return v !== false; }
  function getUndefinedIndex(v, i, a) { return typeof a[i] == 'undefined' ? i : false; }

  var self = this;
  var args = Array.prototype.slice.call(arguments, 1);
  var unargs = args.map(getUndefinedIndex).filter(isnotfalse);

  return function() {
    var iargs = Array.prototype.slice.call(arguments, 0);
    unargs.forEach(function(i, ii) {
      args[i] = iargs[ii];
    });

    return self.apply(context, args);
  };
};

function fargs(a,b,c,d,e,f) {
  console.log(a,b,c,d,e,f);
}

var partfargs = fargs.bindMap(null, 1, undefined, 'mid', undefined, 'end', undefined);
partfargs("second", 3, Number.POSITIVE_INFINITY);