push array key to own array

Question

I'm struggling to work out how I can push my array keys to an array of its own which I'm eventually going to use as column headings.

The below successfully logs my keys however the push is breaking

    let cols = []

    data.forEach(function (obj, index) {
      if (index === 0)
      {
        console.log(Object.keys(obj));
        this.cols.push(Object.keys(obj));
    }
    });

I don't actually have to loop the whole data object either I only need the first index but 1 step at a time!

My end result I expect would be cols = ["ValueDate", "AccountName", "Holding"]

Any thoughts please

Thnaks GWS

Data Extract:

[
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHAUD",
    "Holding": 318622.53
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHCAD",
    "Holding": 7195
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHEUR",
    "Holding": 5077.97
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHGBP",
    "Holding": 19625
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHJPY",
    "Holding": 16463
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHNZD",
    "Holding": 601.56
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHSGD",
    "Holding": 1000
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHUSD",
    "Holding": 1716906.25
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHAUD",
    "Holding": 318622.53
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHCAD",
    "Holding": 7195
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHEUR",
    "Holding": 5077.97
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHGBP",
    "Holding": 19625
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHJPY",
    "Holding": 16463
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHNZD",
    "Holding": 601.56
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHSGD",
    "Holding": 1000
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHUSD",
    "Holding": 1720781.25
  }
]

`Object.keys()` returns an array, so this might help http://stackoverflow.com/questions/4156101/javascript-push-array-values-into-another-array — artem, Apr 28 '17 at 01:59

score 2 · Accepted Answer · answered Apr 28 '17 at 02:00

If you only need to look at the first index anyway, just use Object.keys(data[0]). see working example below.

data = [
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHAUD",
    "Holding": 318622.53
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHCAD",
    "Holding": 7195
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHEUR",
    "Holding": 5077.97
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHGBP",
    "Holding": 19625
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHJPY",
    "Holding": 16463
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHNZD",
    "Holding": 601.56
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHSGD",
    "Holding": 1000
  },
  {
    "ValueDate": "2017-04-26T14:16:00",
    "AccountName": "CASHUSD",
    "Holding": 1716906.25
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHAUD",
    "Holding": 318622.53
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHCAD",
    "Holding": 7195
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHEUR",
    "Holding": 5077.97
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHGBP",
    "Holding": 19625
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHJPY",
    "Holding": 16463
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHNZD",
    "Holding": 601.56
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHSGD",
    "Holding": 1000
  },
  {
    "ValueDate": "2017-04-27T14:16:00",
    "AccountName": "CASHUSD",
    "Holding": 1720781.25
  }
]

let cols = Object.keys(data[0])
console.log(cols)

score 0 · Answer 2 · answered Apr 28 '17 at 02:03

0

use

for(var key in obj){
}

data.forEach(function (obj, index) {
  if(index == 0){
    for(var key in obj){
       console.log(key);
    }
  }  
});

to loop through the object and get the key values

answered Apr 28 '17 at 02:03

subramanian

1,125
1
12
12

score 0 · Answer 3 · answered Apr 28 '17 at 02:26

0

let cols = []

data.forEach(function (obj, index) {
  if (index === 0)
  {
    console.log(Object.keys(obj));
    cols.push(Object.keys(obj));
 }
});

console.log(cols)

answered Apr 28 '17 at 02:26

arcsin1

54
3

push array key to own array

3 Answers3