clones an existing function. scope not included.

cloneFn.js

function cloneFn( fn ) {
  var
    str = fn.toString(),
    args = str.match( /\((.*)\)/ )[1].split(/\W+/),
    body = str.match( /{((?:.|\n)+)}/ )[1];
    
  return Function.apply( this, args.concat( body ) );
};