Question

I would like to compare the values of keys in a JSON object before appending to the object, and if they are the same, add the values instead of appending.

I have:

 {"carset": {
          "location1": [
                      {"car": "volvo", "count": 5},
                      {"car": "mazda", "count": 7},
                      {"car": "toyota", "count": 10},
                     ]
             }
  }

and when i hit this in my for loop:

newcar = 'volvo';
newcount = 6;
cars[i] = ({car: newcar, count: newcount});

I’d like to notice that volvo is already in the json object, and just add the newcount to the existing count. Thanks!

Answer 1

You need to compare with all the items in the location1 array or you can restructure your JSON to make the comparison easier

json = {
 'carset' : {
    'location-cars' : {
      'volvo'  : 5,
      'mazda'  : 7,
      'toyota' : 10
    }
  }
}

function addCar(cars, car) {
  var theCar = cars[car];
   if ( theCar == undefined ) {
      cars[car] = 1;
   } else {
      cars[car] = theCar + 1;
   }
   return cars[car];
}

addCar(json.carset['location-cars'], 'volvo');