Turning an array into an array of objects

Question

How do I turn this array with keys

> dd
[ 'DeviceName',
  'counter1',
  'counter2',
  'counter3',
  'counter4' ]

into this object array with objects

[
    { data: 'DeviceName' },
    { data: 'counter1' },
    { data: 'counter2' },
    { data: 'counter3' },
    { data: 'counter4' }
]

I have tried this function, but the problem is that the data key is the same in them all.

Is there a way around this?

 newdd=function toObject(arr) {
      var rv = {};
      var a =[];
        for (var i = 0; i < arr.length; ++i) {
        rv["data"] = arr[i];
        a.push(rv);
        }
      return a;
    }

This gives me:

> newdd(dd)
[ { data: 'counter4' },
  { data: 'counter4' },
  { data: 'counter4' },
  { data: 'counter4' },
  { data: 'counter4' } ]

think this might be what I want

HattrickNZ
– HattrickNZ

2015-09-03 00:14:38 +00:00
Commented Sep 3, 2015 at 0:14 — HattrickNZ
– HattrickNZ, Commented Sep 3, 2015 at 0:14

Siguza · Accepted Answer · 2015-09-03 00:18:02Z

5

Array.prototype.map():

dd.map(function(element)
{
    return { data: element };
});

answered Sep 3, 2015 at 0:18

Siguza

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Comments

Community · Accepted Answer · 2017-05-23 12:30:14Z

That's because objects in JavaScript are passed by reference (or really call by sharing), not by value, so you're always referencing the same object.

Just move your assignment for rv = {} inside your for loop and it should fix your problem. Reassigning rv to a new object as opposed to modifying the existing instance will result in the desired behavior.

newdd = function toObject(arr) {
    var a =[];
    for (var i = 0; i < arr.length; ++i) {
        var rv = {};
        rv["data"] = arr[i];
        a.push(rv);
    }

    return a;
 }

See Working with objects on the Mozilla Developer Network to help build your understanding of objects.

Andy · Accepted Answer · 2015-11-16 16:58:16Z

2

Try this instead:

function toObject(arr) {
    var a =[];
    for (var i = 0; i < arr.length; ++i) {
        a.push({ data: arr[i] });
    }
    return a;
}

edited Nov 16, 2015 at 16:58

answered Sep 3, 2015 at 0:17

Andy

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