Merging 2 arrays of objects to create a Map of Objects

Question

I'm receiving the following data in my JS from a WebService :

{
  "fire": {
    "totalOccurence": 2,
    "statsByCustomer": [
      {
        "idCustomer": 1,
        "occurence": 1
      },
      {
        "idCustomer": 2,
        "occurence": 1
      }
    ]
  },
  "flood": {
    "totalOccurence": 1,
    "statsByCustomer": [
      {
        "idCustomer": 1,
        "occurence": 1
      }
    ]
  }
}

What's the fastest way to create the following object as a result :

{
  "1": {
    "fire": 1,
    "flood": 1
  },
  "2": {
    "fire": 1,
    "flood": 0
  }
}

I'm actually doing multiple forEach to format the data myself, but i think it's pretty ugly and not efficient.. PS : the key for the result map is the customer Id

Any idea on how to do this the right way?

Thanks for your help !

I'm actually doing multiple forEach Can you please show us? — Rajesh Dixit
– Rajesh Dixit, Commented Feb 20, 2017 at 10:21

Nina Scholz · Accepted Answer · 2017-02-20 10:29:30Z

2

You could iterate the outer object's keys and then the inner arrays. If an result object does not exist, create one with the wanted keys and zero values.

var data = { fire: { totalOccurence: 2, statsByCustomer: [{ idCustomer: 1, occurence: 1 }, { idCustomer: 2, occurence: 1 }] }, flood: { totalOccurence: 1, statsByCustomer: [{ idCustomer: 1, occurence: 1 }] } },
    result = {},
    keys = Object.keys(data);

keys.forEach(function (k) {
    data[k].statsByCustomer.forEach(function (a) {
        if (!result[a.idCustomer]) {
            result[a.idCustomer] = {};
            keys.forEach(function (kk) {
                result[a.idCustomer][kk] = 0;
            });
        }
        result[a.idCustomer][k] += a.occurence;
    });
});

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Feb 20, 2017 at 10:29

Nina Scholz

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1 Comment

Rajesh Dixit Over a year ago

Please let OP share effort.

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