ericmbarnard/Knockout-Validation — pull request #18 by michalporeba (2012-01-30 23:21:54+00:00)
Title: new validators:

This commit adds three new validators
* equal - can be used to enforce user confirming something with checkbox or to compare two password boxes
* notEqual - can be used to force user to select option from a dropdown or to enforce. could be also used to make sure to fields (phone numbers for instance) are different
* unique - checks if the value is unique within a collection

additionally I have changed email validator to accept empty string as I think that if email is really mandatory then it should be explicitly said with required validator. It will also result in more user friendly messages.

I have added getValue() to utils that is similar to ko.utils.unwrapObservable but works on any function.
I then used it to allow validation parameters to be passed as object, function, observable or function returning an observable. It allows to build more complex validation rules.