To format javascript Object with Array of Objects to Array Of Arrays

Question

I have the below object which has array of objects. I want format this object to object of Array of arrays

var object1 = {
  "Usa": [{
    "period": "2018-11-03T00:00:00.000+0000",
    "qty": 1
  }, {
    "period": "2018-11-04T00:00:00.000+0000",
    "qty": 2
  }],
  "india": [
    {
      "period": "2018-19-03T00:00:00.000+0000",
      "qty": 2
    }, {
      "period": "2018-19-04T00:00:00.000+0000",
      "qty": 3
    }
  ]
}

export const createDataPoint = (period, qty) => {
  return [
    Date.now(time),
    Math.round((Math.random() * 100) * 2) / 2 + quantity,

  ];
};

export function createData(object1) {
  let data = [];
  let total = [];
  Object.keys(object1).map(function(item, index) {
    object1[item].map(function(item2, index2) {
      data.push(createDataPoint(item2.period, item2.qty));
    })
    object1[item] = data
  })
  // console.log(object1)
  return object1;
}

But the output is, in every array there are 4 arrays instead of 2 respective arrays. Which means in every array, i am getting total arrays of size 4.

Expected output is

  var object1={
     "Usa":[
      ["123245235",1],
      ["21423435",2]
     ],
    "india":[   
       ["234325436",2],
        ["23422464",3]
    ]    
  }

charlietfl · Accepted Answer · 2018-11-13 01:00:47Z

1

Just reassign each array to new mapped array

const createDataPoint = ({period, qty})=>{
    // do your processing here, just returning period & qty for simplicity 
    return [period, qty]
}

Object.keys(data).forEach(k=>{
    data[k] = data[k].map(createDataPoint);
})

console.log(data)

<script>
  const data = {
    "Usa": [{
      "period": "2018-11-03T00:00:00.000+0000",
      "qty": 1
    }, {
      "period": "2018-11-04T00:00:00.000+0000",
      "qty": 2
    }],
    "india": [{
        "period": "2018-19-03T00:00:00.000+0000",
        "qty": 2
      }, {
        "period": "2018-19-04T00:00:00.000+0000",
        "qty": 3
      }

    ]
  }
</script>

edited Nov 13, 2018 at 1:00

answered Nov 13, 2018 at 0:42

charlietfl

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Comments

Ele · Accepted Answer · 2018-11-13 00:50:46Z

This is an alternative using the function Object.entries to get the entries as follow [country, array] and then with the function reduce build the desired output.

The function map will generate the array with tow indexes.

This approach doesn't mutate the original object

var object1={  "Usa":[       {"period": "2018-11-03T00:00:00.000+0000",               "qty": 1           }, {               "period": "2018-11-04T00:00:00.000+0000",               "qty": 2           } ], "india":[   {    "period": "2018-19-03T00:00:00.000+0000",               "qty": 2           }, {               "period": "2018-19-04T00:00:00.000+0000",               "qty": 3           } ]    },
    result = Object.entries(object1).reduce((a, [country, arr]) => {
      return Object.assign(a, {[country]: arr.map(({period, qty}) => [Date.now(period), qty])});
    }, Object.create(null));

console.log(result);

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

Akrion · Accepted Answer · 2018-11-13 03:32:51Z

You can use Array.prototype.reduce & Object.entries:

var obj = { "Usa": [{ "period": "2018-11-03T00:00:00.000+0000", "qty": 1 }, { "period": "2018-11-04T00:00:00.000+0000", "qty": 2 }], "india": [{ "period": "2018-19-03T00:00:00.000+0000", "qty": 2 }, { "period": "2018-19-04T00:00:00.000+0000", "qty": 3 }] }

const result = Object.entries(obj)
  .reduce((r, [k,v]) => (r[k] = v.map(({period, qty}) => [period, qty]), r),{})
console.log(result)

Somewhat simple approach can be done via Object.keys & reduce:

var obj = { "Usa": [{ "period": "2018-11-03T00:00:00.000+0000", "qty": 1 }, { "period": "2018-11-04T00:00:00.000+0000", "qty": 2 }], "india": [{ "period": "2018-19-03T00:00:00.000+0000", "qty": 2 }, { "period": "2018-19-04T00:00:00.000+0000", "qty": 3 }] }

const result = Object.keys(obj)
  .reduce((r, c) => (r[c] = obj[c].map(({period, qty}) => [period, qty]), r),{})
console.log(result)

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