How to merge two objects which have same property name

Question

I would like to merge two objects into one which have same property name. For example,

var a = {
            "user-activity":{
                "name":"INPUT - radio",
                "value":"radio - No"
            }
        };
var b = {
            "user-activity":{
                "name":"INPUT - radio",
                "value":"radio - No"
            }
        };
var c = a.concat(b);

I am expecting output like below.

{
    "user-activity":{
                        "name":"INPUT - radio",
                        "value":"radio - No"
                    },
    "user-activity":{
                        "name":"INPUT - radio",
                        "value":"radio - No"
                    }
};

And not like below.

[{
     "user-activity":{
                        "name":"INPUT - radio",
                        "value":"radio - No"
                        }
},{
     "user-activity":{
                        "name":"INPUT - radio",
                        "value":"radio - No"
                        }
}]

You can't have two keys with the same name. How would you be able to select them later? — JJJ, Aug 31 '17 at 05:56
`keys` are like `primary keys` in database - it needs to be unique. In all languages that have hash map data-structure this will be like this only. Also I guess you need to merge them, it is the same value. — Nishant, Aug 31 '17 at 06:00
Also concat does not create an object but an array (or a string if you are calling it on strings) — mplungjan, Aug 31 '17 at 06:01
@Nishant: Thanks Nishant. Please mention the same under answer so that i can mark this as correct answer. — Green Computers, Aug 31 '17 at 06:02
Lastly I would think most people would want `{ "user-activity":{ "a": { "name":"INPUT - radio", "value":"radio - No" }, "b":{ "name":"INPUT - radio", "value":"radio - No" } };` when they combined — mplungjan, Aug 31 '17 at 06:03
Possible duplicate of [How can I merge properties of two JavaScript objects dynamically?](https://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically) — Nishant, Aug 31 '17 at 07:22

score 0 · Answer 1 · answered Aug 31 '17 at 06:11

0

Having duplicate property names in an object is in no way possible. Probably you need to rethink the scenario where you need to have a solution like this and figure out some alternate solution.

answered Aug 31 '17 at 06:11

Amit Chawla

44
1
6

Nishant · Accepted Answer · 2017-08-31T13:22:32.320

Keys are like Primary Keys / Unique IDs in database to draw an analogy - it needs to be unique because of the way it is implemented. Keys are the important thing, which identifies a value. All languages that have hash table data structures it will be like this only.

Also in your use case, I guess you need to merge them, it is the same value.

You can also check this How can I merge properties of two JavaScript objects dynamically?

How to merge two objects which have same property name

2 Answers2