06. Sums by Town

function sumsByTown(arr) {
    let sums = {};
    for(let i = 0; i < arr.length; i++){
        var obj = JSON.parse(arr[i]);
        if(sums.hasOwnProperty(obj.town)){
            sums[obj.town] += obj.income;
        }
        else {
            sums[obj.town] = obj.income;
        }
    }

    let towns = Object.keys(sums).sort();

    for (let town of towns) {
        console.log(`${town} -> ${sums[town]}`);
    }
}

//sumsByTown(['{"town":"Sofia","income":200}\n' +
//'{"town":"Varna","income":120}\n' +
//'{"town":"Pleven","income":60}\n' +
//'{"town":"Varna","income":70}\n']);