Angular Differences Between Two Models - angularjs

Question

I have an angular application which uses a significantly large shared model. Currently, when a user presses save the entire model is posted to a RESTful service. Ideally I would only like to post the fields that have changed. Since this is a shared model I do not have access to form validation states such as dirty/pristine etc. The idea I can think of is to have two models, the original and the modified and compare these.
Original Model
{
"firstName": "John",
"lastName": "Smith",
"isAlive": true,
"age": 25,
"address": {
"streetAddress": "21 2nd Street",
"city": "New York",
"state": "NY",
"postalCode": "10021-3100"
},
"phoneNumbers": [
{
"id": "123",
"number": "212 555-1234"
},
{
"id": "456",
"number": "646 555-4567"
},
{
"id": "789",
"number": "123 456-7890"
}
],
"children": [],
"spouse": null
}
Changed Model
{
"firstName": "Jane",
"lastName": "Smith",
"isAlive": true,
"age": 50,
"address": {
"streetAddress": "21 2nd Street",
"city": "New York",
"state": "NY",
"postalCode": "10021-3100"
},
"phoneNumbers": [
{
"id": "123",
"number": "1234567890"
},
{
"id": "456",
"number": "646 555-4567"
},
{
"id": "789",
"number": "123 456-7890"
}
],
"children": [],
"spouse": null
}
Data Posted - This is what I need!
{
"firstName": "Jane",
"age": 50,
"phoneNumbers": [
{
"id":"123",
"number": "1234567890"
}
]
}
How can I achieve this? I need the changed fields including any fields called id!

Answer 1

You'll need something like this. Working Fiddle: https://jsfiddle.net/jyyyLaot/
function filter(obj1, obj2) {
var result = {};
for(key in obj1) {
if(obj2[key] != obj1[key]) result[key] = obj2[key];
if(typeof obj2[key] == 'array' && typeof obj1[key] == 'array')
result[key] = arguments.callee(obj1[key], obj2[key]);
if(typeof obj2[key] == 'object' && typeof obj1[key] == 'object')
result[key] = arguments.callee(obj1[key], obj2[key]);
}
return result;
}