Merge Duplicate object in array

Question

I have an array I need to merge duplicate values with the sum of amount. What would be an efficient algorithm

var arr = [{
    item: {
        id: 1,
        name: "Abc"
    },
    amount: 1
}, {
    item: {
        id: 1,
        name: "Abc"
    },
    amount: 2
}, {
    item: {
        id: 2,
        name: "Abc"
    },
    amount: 2
},{
    item: {
        id: 1,
        name: "Abc"
    },
    amount: 2
}]

I need solution as

[{
    item: {
        id: 1,
        name: "Abc"
    },
    amount: 5
}, {
    item: {
        id: 2,
        name: "Abc"
    },
] amount: 2
}]

Does this answer your question? Merge duplicate objects in array of objects — leonheess
– leonheess, Commented May 9, 2022 at 20:30

amrender singh · Accepted Answer · 2018-07-15 09:49:40Z

4

simply use Object.values() with Array.reudce() to merge objects and then get the values:

var arr = [{ item: { id: 1, name: "Abc" }, amount: 1 }, { item: { id: 1, name: "Abc" }, amount: 2 }, { item: { id: 2, name: "Abc" }, amount: 2 },{ item: { id: 1, name: "Abc" }, amount: 2 }];

var result = Object.values(arr.reduce((a,curr)=>{

  if(!a[curr.item.id])
    a[curr.item.id] = Object.assign({},curr); // Object.assign() is used so that the original element(object) is not mutated.
   else 
     a[curr.item.id].amount += curr.amount;
    return a;
},{}));

console.log(result);

edited Jul 15, 2018 at 9:49

answered Jul 15, 2018 at 9:35

amrender singh

8,2594 gold badges27 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

SirPilan · Accepted Answer · 2018-07-15 10:27:29Z

1

used map to catch em all :D

var arr = [{ item: { id: 1, name: "Abc" }, amount: 1 }, { item: { id: 1, name: "Abc" }, amount: 2 }, { item: { id: 2, name: "Abc" }, amount: 2 },{ item: { id: 1, name: "Abc" }, amount: 2 }];

var res = {};
arr.map((e) => {
  if(!res[e.item.id]) res[e.item.id] = Object.assign({},e); // clone, credits to: @amrender singh
  else res[e.item.id].amount += e.amount;
});
console.log(Object.values(res));

edited Jul 15, 2018 at 10:27

answered Jul 15, 2018 at 10:21

SirPilan

4,8872 gold badges15 silver badges28 bronze badges

Collectives™ on Stack Overflow

Merge Duplicate object in array

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related