Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17


Generate a Copy of a Function

Posted on 2008-06-23
Medium Priority
Last Modified: 2008-06-25
I'm looking to copy a function, override it, and use the copy where I overrided the function.

For example:
file: fns.js, function test(a, b){ return (a+b)};
file: index.html
var oldFn = test;

function test(a,b) {
  return oldFn(a+2, b-2);

index.html is including fns.js.

The error I'm seeing is "Too many recursive calls." Which is leading me to believe that the oldFn var is being replaced with the new declration of "test", so it's calling itself.

I've done a lot of searching and haven't found anything that could help. There's a lot of examples of object copying (which I've tried, with no luck), but nothing with function copying.

Thanks in advance
Question by:AWarrenM
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2

Author Comment

ID: 21851556
increased point value.
LVL 43

Expert Comment

by:David S.
ID: 21852563
Which browser(s) did you get that error message in?

Author Comment

ID: 21856153
Firefox for right now. Didn't test it in IE.

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.


Author Comment

ID: 21862160
Bumping again..
LVL 43

Accepted Solution

David S. earned 1200 total points
ID: 21862196
Ah. I should have tested with your exact code earlier.

Try using an anonymous function when you redefine it:
function test(a, b){ return (a+b)};
var oldFn = test;
test=function(a,b) {
  return oldFn(a+2, b-2);

Open in new window


Author Comment

ID: 21867768
Wow Krav.. I thought I tried that. But I looked back and noticed I had  test  = new function...

Silly silly.

Thank you.

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

JavaScript can be used in a browser to change parts of a webpage dynamically. It begins with the following pattern: If condition W is true, do thing X to target Y after event Z. Below are some tips and tricks to help you get started with JavaScript …
Nothing in an HTTP request can be trusted, including HTTP headers and form data.  A form token is a tool that can be used to guard against request forgeries (CSRF).  This article shows an improved approach to form tokens, making it more difficult to…
The viewer will learn the basics of jQuery, including how to invoke it on a web page. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery.: (CODE)
The viewer will learn the basics of jQuery including how to code hide show and toggles. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery…

670 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question