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]
 ] 
 }

Answer 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>

Answer 2

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; }

Answer 3

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)