Sort object properties by name like another array

Question

how can I sort object properties by name using another array as refer?

var json = '{"b":90,"c":42, "a":34}';
var obj = JSON.parse(json);

var sorting = ["a","b","c"];

I would like to have obj properties ordered just like sorting array

Thank you

Bye

here you can find something similar in php: http://stackoverflow.com/questions/348410/sort-an-array-based-on-another-array — rPulvi, May 20 '14 at 07:59
The downvoted answer is the correct one, there is no guaranteed order in objects, so it can't be sorted, it's that simple. — user3649503, May 20 '14 at 07:59

score 0 · Answer 1 · answered May 20 '14 at 07:52

0

var sorting = Object.keys(obj).sort();

answered May 20 '14 at 07:52

OrangeDog

36,653
12
122
207

score 0 · Answer 2 · answered May 20 '14 at 07:53

0

Javascript objects are not ordered. So, you cannot actually sort them.

answered May 20 '14 at 07:53

Jashwant

28,410
16
70
105

gravi is maybe looking for an algorithm to sort the json array, not a library function. – rPulvi May 20 '14 at 07:57
1

There's no such thing as json array. Also, he is trying to sort object which is not possible. – Jashwant May 20 '14 at 07:58

score 0 · Answer 3 · answered May 20 '14 at 07:58

Why not just iterating over the array, and then access obj properties ?

for ( var i = 0; i < sorting.length; ++i ) {
  var current = obj[ sorting[ i ] ];
  // other stuff here...
}

If you don't intent to iterate over the obj, please explain your actual needs.

score 0 · Answer 4 · answered May 20 '14 at 08:02

Convert Object to Array

var jsonArray = [];

$.each(myObj, function(i,n) { jsonArray.push(n); });
Sort Array

var jsonArraySort = jsonArray.sort();
Convert Array to Object

var jsonSort = {}; for(var i = 0; i < jsonArraySort.length; i++) { jsonSort[i] = jsonArraySort[i]; }

score 0 · Answer 5 · answered May 20 '14 at 08:08

0

You could try something like:

var sorted = []
for (i = 0; i < sorting.length; i++) {
  if (json.hasOwnProperty(sorting[i])) {
    sorted.push(json[sorting[i]);        
  }
}

/* sorted will equal [34, 90, 42] */

answered May 20 '14 at 08:08

izb

50,101
39
117
168

Moritz Roessler · Answer 6 · 2014-05-20T08:21:47.603

You cannot order the keys of an object, as per definition,

An ECMAScript object is an unordered collection of properties_{ES3 Specs}

The mechanics and order of enumerating the properties (step 6.a in the first algorithm, step 7.a in the second) is not specified.

Properties of the object being enumerated may be deleted during enumeration. If a property that has not yet been visited during enumeration is deleted, then it will not be visited. If new properties are added to the object being enumerated during enumeration, the newly added properties are not guaranteed to be visited in the active enumeration. A property name must not be visited more than once in any enumeration._{ES5 Specs}

If you want to a sorted array consisting of your objects keys, you can use [Object.keys][4], To get an array of them, which you can then sort.

var obj = {b:90,c:42, a:34}
console.log (
      Object.keys (obj).sort ()
) // ["a","b","c"]

If you are interested in a sorted array, containing both, keys and values, you could do the following.

var obj = {b: 90, c: 42, a: 34},
    srt = Object.keys(obj).sort().map(function (prop) {
              return {
                  key: prop,
                  value: obj[prop]
              }
          });

console.log(srt) //[{"key":"a","value":34},{"key":"b","value":90},{"key":"c","value":42}]

Sort object properties by name like another array

6 Answers6