I have a json file with multiple `transactions` with a `date` and a `price` attribute. Now I want to compare the dates and if they are in the same month and year I want to sum up the prices.

JSON:

```
transactions: [
{
  date: "2017-11-17",
  price: "28",
},
{
  ...
}

```

JavaScript:

```
request.onload = function() {
  for(const transaction of request.response.transactions) {
    let year = new Date(transaction.date).getFullYear();
    let month = new Date(transaction.date).getMonth();

    console.log(year + ' ' + month);  // output: 2017-11 ...
  }
};

```

I tried to loop over the json object but I struggle to find a solution to compare the dates.