Reorder Json Object keys in typescript

Question

For example the following

[
    {'1000': '', '5000': '', '10000': '', 'Name': 'test1', 'Email': 'test1@gmail.com', 'Reason': ''},
    {'1000': '', '5000': '', '10000': '', 'Name': 'test2', 'Email': 'test2@gmail.com', 'Reason': ''}
]

Is there a way to reorder like:

[
    {'Name': 'test1', 'Email': 'test1@gmail.com', '1000': '', '5000': '', '10000': '', 'Reason': ''},
    {'Name': 'test2', 'Email': 'test2@gmail.com', '1000': '', '5000': '', '10000': '', 'Reason': ''}
]

[No, there is not](https://stackoverflow.com/questions/5525795/does-javascript-guarantee-object-property-order). — Alexander Leonov, Jun 07 '19 at 03:50
Your example isn't clear. Will you add a more clear example please? — Julian Liu, Jun 07 '19 at 03:53

score 0 · Answer 1 · edited Jun 20 '20 at 09:12

In your specific case, the answer is no. Although ES6 (along with modern browser standards and implementations) guarantee the order of object properties, there's one major exception: integer indices.

Due to your object having keys like '1000', '5000', and '10000', you won't be able to achieve the order you desire; these integer indices will always be first.

Property keys are traversed in the following order:

First, the keys that are integer indices in ascending numeric order.

Then, all other string keys, in the order in which they were added to the object.

[...]

Roughly, an integer index is a string that, if converted to a 53-bit non-negative integer and back is the same value. Therefore:

'10' and '2' are integer indices.

'02' is not an integer index. Coverting it to an integer and back results in the different string '2'.

'3.141' is not an integer index, because 3.141 is not an integer.

(Source)

And a brief example:

const obj = {
  "Z": 1,
  "B": 2,
  "C": 3
};

console.log(obj);   //Maintains creation order

const obj2 = {
  "A": 1,
  "B": 2,
  "100": 3
}

console.log(obj2);  //Does not maintain creation order

score 0 · Answer 2 · answered Jun 07 '19 at 06:18

0

The order of object properties should not matter. If it does you have a bad design at hand. The best approach is to rethink your design.

answered Jun 07 '19 at 06:18

stormpat

5,099
3
23
29

Reorder Json Object keys in typescript

2 Answers2