KnockoutJS IsDirty Extender

knockoutextensions.js

//  Used to give an observable the ability to track whether or not its
//  values have been changed.  Adapted from a few blog posts:
//  http://www.knockmeout.net/2011/05/creating-smart-dirty-flag-in-knockoutjs.html
//  http://schinckel.net/2012/01/14/knockoutjs-dirty-extender./ 
//
//  Requires:  knockout.js, knockout.js mapping extension

ko.extenders.dirty = function(target) {
    var cleanValue = ko.observable(ko.mapping.toJSON(target));
  
    target.isDirty = ko.computed(function(){
    return ko.mapping.toJSON(target) !== cleanValue();
    });
    return target;
};

//  When working with an array containing items that could be dirty, use
//  you can quickly use the grep function in jQuery to extract those.

 $.grep([ARRAY], function(n,i){ return [SOME CONDITION]  })