Mapping object to array in js

Question

I am beginner in data structure and trying to improve my skills. I am trying to divide the object value to list of other object. So I/P is

1st Object JSON:

let mapMonth ={
    "10": 8,
    "11": 30,
    "12": 31,
    "01": 23
}

where 10 is Oct, 11 is Nov, 12 is Dec and 01 is Jan.

2nd Object JSON:

let mapData = {
    "key1": {
        "subkey1": [
            [407341537, 1666737463, 363248139, 596560162]
        ],
        "subkey2": ["Oct", "Nov", "Dec", "Jan"]
    },
    "key2": {
        "subkey1": [
            [78491802, 334718068, 68299710, 81365082]
        ],
        "subkey2": ["Oct", "Nov", "Dec", "Jan"]
    },
    "key3": {
        "subkey1": [
            [501844, 3362217, 648527, 1073573]
        ],
        "subkey2": ["Oct", "Nov", "Dec", "Jan"]
    }
}

So now I need to divide 407341537 with 8 i.e 50917692.125, 1666737463 with 30 i.e 55557915.4333 and so on.. Expected output:

{
    "key1": {
        "subkey1": [
            [50917692.125, 55557915.4333, 11717681.9,72466846.2174]
        ],
        "subkey2": ["Oct", "Nov", "Dec", "Jan"]
    },
    "key2": {
        "subkey1": [
            [9811475.25, 11157268.9333, 2203216.45161, 3537612.26087]
        ],
        "subkey2": ["Oct", "Nov", "Dec", "Jan"]
    },
    "key3": {
        "subkey1": [
            [62730.5, 112073.9, 20920.225, 46677.086]
        ],
        "subkey2": ["Oct", "Nov", "Dec", "Jan"]
    }
}

Code I have tried:

let averageObj = {};
var count = 0;
for (let key in mapData) {
  averageObj[key] = [];
  mapData[key]['subkey1'][0].forEach((data, index) => {
    for (let monthKey in mapMonth) {
      averageObj[key].push(data / mapMonth[monthKey]);
    }
  });
}

Please let me know if you need anything else.

So, in short: the mapMonth["10"] value should be used to divide the value of mapData.keyX.subkeyX[0], is that correct? — Calvin Nunes
– Calvin Nunes, Commented Jan 23, 2020 at 17:09

Ele · Accepted Answer · 2020-01-23 17:14:08Z

1

Assuming an object with fixed keys and nested array with only one index:

This approach mutates the original object.

let mapMonthDesc = {"Oct": "10","Nov": "11","Dec": "12","Jan": "01"},
    mapMonth = {"10": 8,"11": 30,"12": 31,"01": 23},
    mapData = {"key1": {"subkey1": [[407341537, 1666737463, 363248139, 596560162]],"subkey2": ["Oct", "Nov", "Dec", "Jan"]},"key2": {"subkey1": [[78491802, 334718068, 68299710, 81365082]],"subkey2": ["Oct", "Nov", "Dec", "Jan"]},"key3": {"subkey1": [[501844, 3362217, 648527, 1073573]],"subkey2": ["Oct", "Nov", "Dec", "Jan"]}};

Object.values(mapData).forEach(({subkey1: [numbers], subkey2}) => {
  numbers.forEach((n, i) => numbers[i] = n / mapMonth[mapMonthDesc[subkey2[i]]]);
});

console.log(mapData);

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answered Jan 23, 2020 at 17:14

Ele

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1 Comment

rohit Over a year ago

Great !! Thank you can you please add comment so I can understand better

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