How can I get a list of the differences between two JavaScript object graphs?

Question

I want to be able to get a list of all differences between two JavaScript object graphs, with the property names and values where the deltas occur.

For what it is w

Answer 1

Here is a partial, naïve solution to my problem - I will update this as I further develop it.

function findDifferences(objectA, objectB) {
   var propertyChanges = [];
   var objectGraphPath = ["this"];
   (function(a, b) {
      if(a.constructor == Array) {
         // BIG assumptions here: That both arrays are same length, that
         // the members of those arrays are _essentially_ the same, and 
         // that those array members are in the same order...
         for(var i = 0; i < a.length; i++) {
            objectGraphPath.push("[" + i.toString() + "]");
            arguments.callee(a[i], b[i]);
            objectGraphPath.pop();
         }
      } else if(a.constructor == Object || (a.constructor != Number && 
                a.constructor != String && a.constructor != Date && 
                a.constructor != RegExp && a.constructor != Function &&
                a.constructor != Boolean)) {
         // we can safely assume that the objects have the 
         // same property lists, else why compare them?
         for(var property in a) {
            objectGraphPath.push(("." + property));
            if(a[property].constructor != Function) {
               arguments.callee(a[property], b[property]);
            }
            objectGraphPath.pop();
         }
      } else if(a.constructor != Function) { // filter out functions
         if(a != b) {
            propertyChanges.push({ "Property": objectGraphPath.join(""), "ObjectA": a, "ObjectB": b });
         }
      }
   })(objectA, objectB);
   return propertyChanges;
}

And here is a sample of how it would be used and the data it would provide (please excuse the long example, but I want to use something relatively non-trivial):

var person1 = { 
   FirstName : "John", 
   LastName : "Doh", 
   Age : 30, 
   EMailAddresses : [
      "john.doe@gmail.com", 
      "jd@initials.com"
   ], 
   Children : [ 
      { 
         FirstName : "Sara", 
         LastName : "Doe", 
         Age : 2 
      }, { 
         FirstName : "Beth", 
         LastName : "Doe", 
         Age : 5 
      } 
   ] 
};

var person2 = { 
   FirstName : "John", 
   LastName : "Doe", 
   Age : 33, 
   EMailAddresses : [
      "john.doe@gmail.com", 
      "jdoe@hotmail.com"
   ], 
   Children : [ 
      { 
         FirstName : "Sara", 
         LastName : "Doe", 
         Age : 3 
      }, { 
         FirstName : "Bethany", 
         LastName : "Doe", 
         Age : 5 
      } 
   ] 
};

var differences = findDifferences(person1, person2);

At this point, here is what the differences array would look like if you serialized it to JSON:

[
   {
      "Property":"this.LastName", 
      "ObjectA":"Doh", 
      "ObjectB":"Doe"
   }, {
      "Property":"this.Age", 
      "ObjectA":30, 
      "ObjectB":33
   }, {
      "Property":"this.EMailAddresses[1]", 
      "ObjectA":"jd@initials.com", 
      "ObjectB":"jdoe@hotmail.com"
   }, {
      "Property":"this.Children[0].Age", 
      "ObjectA":2, 
      "ObjectB":3
   }, {
      "Property":"this.Children[1].FirstName", 
      "ObjectA":"Beth", 
      "ObjectB":"Bethany"
   }
]

The this in the Property value refers to the root of the object that was compared. So, this solution is not yet exactly what I need, but it is pretty darn close.

Hope this is useful to someone out there, and if you have any suggestions for improvement, I am all-ears; I wrote this very late last night (i.e. early this morning) and there may be things I am completely overlooking.

Thanks.