Reshape/Unpivot javascript array of objects

Question

I've a druid cluster that I'm querying with the plywood library.

Data are retrieved as arrays of objects. Everything is fine, but now I've now to reshape those data to have a better visualization in my table.

This is my array:

var x_start = [ 
{ split: 'no', c1: 345, c2: 763, c3: 12 }, 
{ split: 'yes', c1: 293, c2: 1283, c3: 46 },
];

x_start will always have 2 object with the same keys.

And this is what i want to accomplish:

var x_target = [
  { cluster: 'c1', no: 345, yes: 293 },
  { cluster: 'c2', no: 763, yes: 1283 },
  { cluster: 'c3', no: 12, yes: 46 },
];

I made some researches and I understand that the best solution is probably to use a combination of map for accessing the objects and then reshaping them, but I'm in trouble to find the correct way to do that.

Any suggestion?

Shuvojit Saha · Accepted Answer · 2020-07-10 10:34:33Z

1

You can try with Array.prototype.reduce() and Array.prototype.find() to solve your problem. You can checkout the following solution.

var x_start = [{
    split: 'no',
    c1: 345,
    c2: 763,
    c3: 12
  },
  {
    split: 'yes',
    c1: 293,
    c2: 1283,
    c3: 46
  },
];

const reducer = (acc, x) => {
  const findOrAdd = key => {
    let item = acc.find(v => v.cluster === key);
    if (item) return item;
    item = {
      cluster: key
    };
    acc.push(item);
    return item;
  }

  Object.keys(x).filter(key => key !== 'split')
    .forEach(key => {
      const item = findOrAdd(key);
      item[x.split] = x[key];
    });
  return acc;
}

var x_target = x_start.reduce(reducer, []);
console.log(x_target);

answered Jul 10, 2020 at 10:34

Shuvojit Saha

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Comments

kiritoXF · Accepted Answer · 2020-07-10 09:31:20Z

0

This will work if x_start only has 2 objects and the number of c1, c2..cn in no is equal to c1, c2..cn in yes

const no_arr = Object.entries(x_start[0]);

const yes_arr = Object.entries(x_start[1]);

const x_target = [];

for (let i = 1; i < no_arr.length; i++) {
    x_target.push({
      'cluster': no_arr[i][0],
      'no': no_arr[i][1],
      'yes': yes_arr[i][1]
    })
}

answered Jul 10, 2020 at 9:31

kiritoXF

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