Merge two objects in Javascript

Question

I have two JSON s, I want to add two JSON s in Javascript (Join JSOB object into JSON A),

JSON A :-

{

    "data": [{
        "id": 1,
        "subgroup": "1",
        "power": "2",
        "grp": "1"
    }, {
        "id": 1,
        "subgroup": "1",
        "power": "1",
        "grp": "1"
    }, {
        "id": 2,
        "subgroup": "1",
        "power": "1",
        "grp": "2"
    }, {
        "id": 3,
        "subgroup": "2",
        "power": "1",
        "grp": "2"
    }, {
        "id": 4,
        "subgroup": "1",
        "power": "1",
        "grp": "3"
    }, {
        "id": 5,
        "subgroup": "2",
        "power": "1",
        "grp": "2"
    }, {
        "id": 6,
        "subgroup": "2",
        "power": "1",
        "grp": "1"
    }, {
        "id": 7,
        "subgroup": "1",
        "power": "1",
        "grp": "4"
    }, {
        "id": 1,
        "subgroup": "3",
        "power": "2",
        "grp": "4"
    }

}

JSON B :-

{

    "data": [{
        "id": 1,
        "subgroup": "3",
        "power": "2",
        "grp": "4"
    }, {
        "id": 1,
        "subgroup": "4",
        "power": "1",
        "grp": "3"
    }

}

Key names are similar in JSON A and JSON B . We can see, subgroup 3 and subgroup 4 are only present in grp 4 and grp 3 respectively (look into JSON B). I want to add each subgroup from JSON B into each grp in JSON A (except the grp s where those subgroup s are already present. Like in JSON A there is an entry with subgroup 3 and grp 4, we will skip that.). Value of Id, power will be similar respectively. So, we want to add subgroup 3 in the grp 1, 2, 3 and add subgroup 4 in the group 1, 2, 4 . For subgroup 3, power and id value will be 2, 1 respectively and for subgroup 4, power and id value will be 1, 1 respectively.

Final JSON A output should be,

{

    "data": [{
        "id": 1,
        "subgroup": "1",
        "power": "2",
        "grp": "1"
    }, {
        "id": 1,
        "subgroup": "1",
        "power": "1",
        "grp": "1"
    }, {
        "id": 2,
        "subgroup": "1",
        "power": "1",
        "grp": "2"
    }, {
        "id": 3,
        "subgroup": "2",
        "power": "1",
        "grp": "2"
    }, {
        "id": 4,
        "subgroup": "1",
        "power": "1",
        "grp": "3"
    }, {
        "id": 5,
        "subgroup": "2",
        "power": "1",
        "grp": "2"
    }, {
        "id": 6,
        "subgroup": "2",
        "power": "1",
        "grp": "1"
    }, {
        "id": 7,
        "subgroup": "1",
        "power": "1",
        "grp": "4"
    }, {
        "id": 1,
        "subgroup": "3",
        "power": "2",
        "grp": "4"
    }, {
        "id": 1,
        "subgroup": "3",
        "power": "2",
        "grp": "1"
    }, {
        "id": 1,
        "subgroup": "3",
        "power": "2",
        "grp": "2"
    }, {
        "id": 1,
        "subgroup": "3",
        "power": "2",
        "grp": "3"
    }, {
        "id": 1,
        "subgroup": "4",
        "power": "1",
        "grp": "1"
    }, {
        "id": 1,
        "subgroup": "4",
        "power": "1",
        "grp": "2"
    }, {
        "id": 1,
        "subgroup": "4",
        "power": "1",
        "grp": "4"
    }

}

I can add object into JSON,

var myObj = {
        "id" : id,
        "subgroup" : subgroup,
        "power" : power,
        "grp" : grp

}

What is the recommended way to join into JSON A from JSON B and skip the entries where subgroup is already present in the grp.

what you mean by 'add'? join two lists? count or multiply? – Dmitri Algazin Jul 02 '18 at 16:40 — Dmitri Algazin, Jul 02 '18 at 16:40
This seems more like merging than adding. – Barmar Jul 02 '18 at 16:42 — Barmar, Jul 02 '18 at 16:42

score 0 · Answer 1 · answered Jul 02 '18 at 17:06

JSON when parsed become object.

You can merge the objects like this

ECMAScript 2015 (ES6) Standard Method

/* For the case in question, you would do: */
Object.assign(obj1, obj2);

/** There's no limit to the number of objects you can merge.
 *  All objects get merged into the first object. 
 *  Only the object in the first argument is mutated and returned.
 *  Later properties overwrite earlier properties with the same name. */
const allRules = Object.assign({}, obj1, obj2, obj3, etc);

For more detailed description

visit - How can I merge properties of two JavaScript objects dynamically?

you question is difficult to understand. write clearly and fix spelling mistakes. — Shashank Chaurasia, Jul 02 '18 at 17:18

Merge two objects in Javascript

1 Answers1