Concatenate JS objects

Question

I have two object like below

var data = {
        site_name: "my_site",
        page_id: "page_name",
        city: "New York",
        region_code: "NY",
        country_code: "US"
     },
     user_data = {
        user: "user_name",
        conversion_rate: 1.25
     };

I want to concatenate these two object like below

user_data = {
     user: "user_name",
     conversion_rate: 1.25,
     site_name: "my_site",
     page_id: "page_name",
     city: "New York",
     region_code: "NY",
     country_code: "US"
 };

I did it by looping on second on by checking typeof user_data.key .... and it solved my problem but my curiosity is to do it without looping in an optimized way. Any of your suggestion will be appreciated.

i think jquery's extend( target [, object1 ] [, objectN ] ) is a good option — Sunny Soni, Jul 21 '16 at 09:37
Possible duplicate of [How can I merge properties of two JavaScript objects dynamically?](http://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically) — insan-e, Jul 21 '16 at 09:37

score 3 · Answer 1 · answered Jul 21 '16 at 09:37

3

You can use Object.assign of ES6:

var combined = Object.assign({}, data, user_data);

Or even:

Object.assign(user_data, data); // this will change `user_data`

answered Jul 21 '16 at 09:37

str

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it is not supported by IE – Janie Jul 21 '16 at 09:45
1

@trim ES6 is not supported by IE. You have to use babel. – Dmitri Pavlutin Jul 21 '16 at 09:48
@trim IE only supports a very limited subset of ES6. And as Dmitri mentioned, you have to use a transpiler like [Babel](https://babeljs.io) if you need to support outdated browsers. – str Jul 21 '16 at 10:58

score 1 · Answer 2 · answered Jul 21 '16 at 09:46

If you can use Babel, simply use spread operator on objects:

var data = {
   site_name: "my_site",
   page_id: "page_name",
   city: "New York",
   region_code: "NY",
   country_code: "US"
},
user_data = {
   user: "user_name",
   conversion_rate: 1.25
};

var combined = {
  ...data,
  ...user_data
};

console.log(combined);

Please see the demo.

"Spread properties" is still in proposal stage 2, but you can use it with Babel.
See here more details about this feature.

grateful · Answer 3 · 2016-07-21T09:56:39.590

-1

This would work in your example case on all browsers:

data=JSON.stringify(data);
user_data=JSON.stringify(user_data);
user_data=user_data.replace("}",data.replace("{",","));
user_data=JSON.parse(user_data);

edited Jul 21 '16 at 09:56

answered Jul 21 '16 at 09:48

grateful

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Concatenate JS objects

3 Answers3