best way to convert object with arrays to array with objects and viceversa

Question

what is the best way to convert an object of arrays to an array of objects and vice-versa

{
  category : ['a','b','c'],
  title : ['e','f','g'],
  code : ['z','x','v']
}

To

[
  {
    category : 'a',
    title : 'e',
    code : 'z'
  },
  {
    category : 'b',
    title : 'f',
    code : 'x'
  },
  {
    category : 'c',
    title : 'g',
    code : 'v'
  },
]

Answer 1

You could use two function for generating an array or an object. They works with

• Object.keys for getting all own property names,

• Array#reduce for iterating an array and collecting items for return,

• Array#forEach just fo itarating an array.

function getArray(object) {
    return Object.keys(object).reduce(function (r, k) {
        object[k].forEach(function (a, i) {
            r[i] = r[i] || {};
            r[i][k] = a;
        });
        return r;
    }, []);
}

function getObject(array) {
    return array.reduce(function (r, o, i) {
        Object.keys(o).forEach(function (k) {
            r[k] = r[k] || [];
            r[k][i] = o[k];
        });
        return r;
    }, {});
}

var data = { category: ['a', 'b', 'c'], title: ['e', 'f', 'g'], code: ['z', 'x', 'v'] };

console.log(getArray(data));
console.log(getObject(getArray(data)));

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

Answer 2

You can use map() and forEach()

var obj = {
  category : ['a','b','c'],
  title : ['e','f','g'],
  code : ['z','x','v']
}

var result = Object.keys(obj).map(function(e, i) {
  var o = {}
  Object.keys(obj).forEach((a, j) => o[a] = obj[a][i])
  return o
})

console.log(result)