Can I copy/clone a function in JavaScript?
- by Craig Stuntz
I'm using jQuery with the validators plugin. I would like to replace the "required" validator with one of my own. This is easy:
jQuery.validator.addMethod("required", function(value, element, param) {
return myRequired(value, element, param);
}, jQuery.validator.messages.required);
So far, so good. This works just fine. But what I really want to do is call my function in some cases, and the default validator for the rest. Unfortunately, this turns out to be recursive:
jQuery.validator.addMethod("required", function(value, element, param) {
// handle comboboxes with empty guids
if (someTest(element)) {
return myRequired(value, element, param);
}
return jQuery.validator.methods.required(value, element, param);
}, jQuery.validator.messages.required);
I looked at the source code for the validators, and the default implementation of "required" is defined as an anonymous method at jQuery.validator.messages.required. So there is no other (non-anonymous) reference to the function that I can use.
Storing a reference to the function externally before calling addMethod and calling the default validator via that reference makes no difference.
What I really need to do is to be able to copy the default required validator function by value instead of by reference. But after quite a bit of searching, I can't figure out how to do that. Is it possible?
If it's impossible, then I can copy the source for the original function. But that creates a maintenance problem, and I would rather not do that unless there is no "better way."
