In Javascript I have an array of model objects:

[  
   {  
      "id":13,
      "title":"Some title 1",
      "time": "friday"
      ...
   },
   {  
      "id":15,
      "title":"Some title 3",
      "time": "Saturday"
      ...
   },
   {  
      "id":16,
      ...
   },
   ...
]

(there is more than 2 values and properties on each object) I want to get an object with each id from the array moved to key, like so:

{
  13: {
    title: "Some title 1",
    time: "Friday"
    ...
  },
  15: {
    title: "Some title 3",
    time: "Saturday"
    ...
  },
  16: {
    ...
  },
  ...
}

I am producing the array with Rails view .to_json include: {} syntax, so an answer in rails would also work for me. I will use the result object with Redux for an initial state so some kind of Redux answer is great too. Also would be interested in both es6 and es5 answer (I will use es5 answer though because Rails doesn't pile es6 in views, but later we are porting to client side application where it would also apply).

In Javascript I have an array of model objects:

[  
   {  
      "id":13,
      "title":"Some title 1",
      "time": "friday"
      ...
   },
   {  
      "id":15,
      "title":"Some title 3",
      "time": "Saturday"
      ...
   },
   {  
      "id":16,
      ...
   },
   ...
]

(there is more than 2 values and properties on each object) I want to get an object with each id from the array moved to key, like so:

{
  13: {
    title: "Some title 1",
    time: "Friday"
    ...
  },
  15: {
    title: "Some title 3",
    time: "Saturday"
    ...
  },
  16: {
    ...
  },
  ...
}

I am producing the array with Rails view .to_json include: {} syntax, so an answer in rails would also work for me. I will use the result object with Redux for an initial state so some kind of Redux answer is great too. Also would be interested in both es6 and es5 answer (I will use es5 answer though because Rails doesn't pile es6 in views, but later we are porting to client side application where it would also apply).

• javascript
• ruby-on-rails
• ecmascript-6
• redux
• map-function

6 Answers 6

The simplest solution is to iterate over the array and attach a copy of each item to a new object:

let result = {};
for (let item of data) {
  let newObject = Object.assign({}, item);
  result[newObject.id] = newObject;
  delete newObject.id;
}

If you don't need the data array later on it gets even simpler:

let result = {};
for (let item of data) {
  result[item.id] = item;
  delete item.id;
}

A simple way would be to just iterate through the array in Ruby:

foo = [  
   {  
      "id":13,
      "title":"Some title 1",
      ...
   },
   {  
      "id":15,
      "title":"Some title 3",
      ...
   }]

result = {}
foo.each {|f| result[f.delete('id')] = f}

You can use reduce() to create object and inside you can loop object properties with Object.keys() and forEach() loop to create inner objects.

var data = [{
  "id": 13,
  "title": "Some title 1",
  'lorem': 'ipsum'
}, {
  "id": 15,
  "title": "Some title 3",
}, {
  "id": 16,
}]

var result = data.reduce(function(r, e) {
  r[e.id] = {}
  Object.keys(e).forEach(function(k) {
    if(k != 'id') r[e.id] = Object.assign(r[e.id], {[k]: e[k]})
  })
  return r
}, {})

console.log(result)

Another approach is to use reduce() two times. First one to create one outer object and inner reduce to create each object inside first object.

var data = [{"id":13,"title":"Some title 1","lorem":"ipsum"},{"id":15,"title":"Some title 3"},{"id":16}]

var result = data.reduce(function(r, e) {
  r[e.id] = Object.keys(e).reduce(function(o, a) {
   if(a != 'id') o[a] = e[a]
    return o;
  }, {})
  return r;
}, {})

console.log(result)

return users.reduce((results, u)=> (results[u.id] = u, results), {})

Use below code

try {
            JSONArray jsonArray=new JSONArray("yourJsonString");
            for(int i=0;i<jsonArray.length();i++){


                JSONObject outer_jsonObject=new JSONObject();
                JSONObject inner_jsonObject=new JSONObject();

                inner_jsonObject.put("title",jsonArray.getJSONObject(i).getString("title"));
                outer_jsonObject.put(jsonArray.getJSONObject(i).getString("id"),inner_jsonObject);

            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

I would suggest you following approach.

For every id, assign an object with titles key, holding an array of titles as it's value.

It looks clean and it's easily readable, especially when there's few titles for one id.

var arr=[{id:13,title:"Some title 1"},{id:15,title1:"Some title 3",title2:"Some title 4"},{id:16}],     result = [];

arr.forEach(function(v){
  var obj = {};
  var titles = {};
  var titlesArr = [];
  Object.keys(v).forEach(function(c){
    if (c != 'id') {
      titlesArr.push(v[c]);
      titles.titles = titlesArr;
    }
  });
  obj.id = titles;
  result.push(obj);
});

console.log(result);