Iterate through Object keys and manipulate the key values

Question

I have an array of objects which is coming from server response.

Array structure:

[
  {
    col1: ["a", "b"],
    col2: ["c", "d"]
  },

  {
    col1: ["e", "f"],
    col2: ["g", "h"]
  }
]

I want the desired output array to be in this form:

[
  {
    col1: "b",
    col2: "d"
  },

  {
    col1: "f",
    col2: "h"
  }
]

Basically I want to convert the Object keys Value which is an array initially to a single value and that value will be second element of the Object keys array.

I am able to do the conversion by converting Object Keys array to comma seperated string using toString(), then do string.split(",")[1] but I am not able to iterate through the Object keys.

Would prefer the inputs in ES6 using map for iteration

This can be achieved using simple loops, Have you tried anything? — Satpal, Apr 11 '17 at 13:36
Possible duplicate of [How do I loop through or enumerate a JavaScript object?](http://stackoverflow.com/questions/684672/how-do-i-loop-through-or-enumerate-a-javascript-object) — Arg0n, Apr 11 '17 at 13:37
I am using es6 , using map for looping. I tried double map but countn't iterate in an optmised way. — Harshil Garg, Apr 11 '17 at 13:38

Mμ. · Answer 1 · 2017-04-11T13:45:07.993

0

The code below should work as per your specification.

var arr = [ {col1: ["a","b"], col2: ["c","d"] }, {col1: ["e","f"], col2: ["g","h"] } ]


// [ {col1: "b" , col2: "d" }, {col1: "f", col2: "h" } ]

arr2 = [];

arr.forEach(e => {
  let currObj = {};
  Object.keys(e).forEach(f => {
    currObj[f] = e[f][1]
  })
  arr2.push(currObj)
})

console.log(arr2);

edited Apr 11 '17 at 13:45

answered Apr 11 '17 at 13:38

Mμ.

8,382
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Key names are variable , not fixed as it is coming from server response. – Harshil Garg Apr 11 '17 at 13:40
Works great. Keep it up ! – Harshil Garg Apr 11 '17 at 13:48

score 0 · Answer 2 · answered Apr 11 '17 at 13:41

0

Possible solution using Array#reduce and Object.keys.

var arr = [ {col1: ["a","b"], col2: ["c","d"] }, {col1: ["e","f"], col2: ["g","h"] } ],
    res = arr.reduce(function(s,a) {
      var obj = {};
      Object.keys(a).map(function(c) {
        obj[c] = a[c][1];
      })
      s.push(obj);
      return s;
    }, []);
    
    console.log(res);

answered Apr 11 '17 at 13:41

kind user

40,029
7
67
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Thanks. This is what I was looking for. Works like a charm. – Harshil Garg Apr 11 '17 at 13:44

score 0 · Accepted Answer · answered Apr 11 '17 at 15:51

You could use a combination of Array#map, Object.assign and spread syntax ... with an inner mapping of a new object with the wanted key/value.

var data = [{ col1: ["a", "b"], col2: ["c", "d"] }, { col1: ["e", "f"], col2: ["g", "h"] }],
    result = data.map(o => Object.assign({}, ...Object.keys(o).map(k => ({ [k]: o[k][1] }))));

console.log(result);

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Iterate through Object keys and manipulate the key values

3 Answers3