Convert object with multiple arrays to array of objects

Question

I stuggle a lot with data I get from an API:

This is the way the data gets returned, the amout of arrays differs.

const objData = {
    arr1: [1,2,3],
    arr2: [1,2,1],
    arr3: [2,1,2],
    arr4: ["a","b", "c"]
}

This is the way it SHOULD look

const desired = [
    {a: 1, b: 1, c: 2, d: "a"},
    {a: 2, b: 2, c: 1, d: "b"},
    {a: 2, b: 1, c: 2, d: "c"}
]

This gives me the desired result, but it is not dymanic, since I have to provide the names of the arrays, and the amount of arrays in the object is not allowed to change.

const DataObj = []

for (let i = 0; i < objData.arr1.length; i++) {
    const objX = {
        a: objData.arr1[i],
        b: objData.arr2[i],
        c: objData.arr3[i],
        d: objData.arr4[i],
    }
    DataObj.push(objX)
}

Can anybody help me to solve this? How can I make this independent from the names of the arrays and the amount of arrays in the dataset?

How you are deciding the key for {a: 1, b: 1, c: 2, d: "a"}, like a, b, c and d. Is there any logic for it ? — simbathesailor
– simbathesailor, Commented Aug 28, 2020 at 7:54

Nina Scholz · Accepted Answer · 2020-08-28 07:55:25Z

3

You could map the arrays with new objects.

const
    objData = { arr1: [1, 2, 3], arr2: [1, 2, 3], arr3: [2, 1, 2], arr4: ["a", "b", "c"] },
    keys = { arr1: 'a', arr2: 'b', arr3: 'c', arr4: 'd' },
    result = Object
        .entries(objData)
        .reduce((r, [key, array]) => array.map((v, i) => ({ ...r[i], [keys[key]]: v  })), []);
        
console.log(result);

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

answered Aug 28, 2020 at 7:55

Nina Scholz

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Comments

EugenSunic · Accepted Answer · 2020-08-28 09:01:31Z

Non functional approach, use integers to get your letters

const objData = {
  arr1: [1, 2, 3, 5],
  arr2: [1, 2, 1, 4],
  arr3: [2, 1, 2, 3],
  arr4: ["a", "b", "c", "d"]
}



const len = Object.values(objData)[0].length;
let cnt = 97;
let newObj = {};
const list = [];

for (let i = 0; i < len; i++) {
  for (let key in objData) {
    newObj[String.fromCharCode(cnt)] = objData[key][i];
    ++cnt
  }
  list.push(newObj);
  cnt = 97;
  newObj = {};
}

console.log(list)

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