Difference in JSON objects using Javascript/JQuery

Question

I have two JSON objects in Javascript, identical except for the numerical values. It looks like this:

var data = {
  "eth0":{"Tx":"4136675","Rx":"13232319"},
  "eth1":{"Tx":"4","Rx":"0"},
  "lo":{"Tx":"471290","Rx":"471290"}
}

var old = {
  "eth0":{"Tx":"4136575","Rx":"13232219"},
  "eth1":{"Tx":"4","Rx":"0"},
  "lo":{"Tx":"471290","Rx":"471290"}
}

One object called "data" has the current values, another object called "old" has the same values from 1 second ago. I'd like to output a JSON object with only the change in values so I can calculate data throughput on the network interfaces.

var throughput = {
  "eth0":{"Tx":"100","Rx":"100"},
  "eth1":{"Tx":"0","Rx":"0"},
  "lo":{"Tx":"0","Rx":"0"}
}

I'm not sure how to go about traversing the JSON data - it could be for any number of interfaces.

Can anyone please lend me a hand? Thanks in advance

Answer 1

did you look at : http://tlrobinson.net/projects/js/jsondiff/ I think this is what you are looking for. :)

Answer 2

The basic premise for iterating over objects in JavaScript is like so

var whatever = {}; // object to iterate over
for ( var i in whatever )
{
  if ( whatever.hasOwnProperty( i ) )
  {
     // i is the property/key name
     // whatever[i] is the value at that property
  }
}

Fixing up a checker wouldn't be too hard. You'll need recursion. I'll leave that as an exercise for you or another SOer.

Answer 3

You can iterate trough the parent and child object properties:

var diff = {};
for(var p in data){
  if (old.hasOwnProperty(p) && typeof(data[p]) == 'object'){
    diff[p] = {};
    for(var i in data[p]){
      if (old[p].hasOwnProperty(i)){
        diff[p][i] = data[p][i] - old[p][i];
      }
    }
  }
}