Question

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.’

Answer 1

Storing a reference to the function externally before calling addMethod and calling the default validator via that reference makes no difference.

That’s exactly what should work.

jQuery.validator.methods.oldRequired = jQuery.validator.methods.required;  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.oldRequired(value, element, param); }, jQuery.validator.messages.required); 

This should work too: (And the problem with this is solved)

var oldRequired = jQuery.validator.methods.required; jQuery.validator.addMethod('required', function(value, element, param) {     // handle comboboxes with empty guids     if (someTest(element)) {         return myRequired(value, element, param);     }     return oldRequired.call(this, value, element, param);     // return jQuery.oldRequired.apply(this, arguments); }, jQuery.validator.messages.required);