Removing duplicates while adding their values in an array

Question

Lets say we have an array also with empty strings

const arr = [
  { value: 1, name: "king" },
  { value: 2, name: "master" },
  { value: 10, name: "lisa" },
  { value: 4, name: "lisa" },
  { value: 5, name: "jim" },
  { value: 6, name: "master" },
  { value: 1, name: "jim" },
  { value: 3, name: "" },
  { value: 2, name: "" },
]

I want to remove the duplicate names and add their values into same array or another array. Desired output:

[
  { value: 1, name: "king" },
  { value: 8, name: "master" },
  { value: 14, name: "lisa" },
  { value: 6, name: "jim" },
  { value: 5, name: "" },
]

What have you tried so far? It seems like a simple loop or `.reduce()` case — Sebastian Kaczmarek, Feb 17 '20 at 12:29

Manu Varghese · Accepted Answer · 2020-02-17T13:05:44.487

0

By simply looping checking for repetition, you can reduce array.

arr = [
  { value: 1, name: "king" },
  { value: 2, name: "master" },
  { value: 10, name: "lisa" },
  { value: 4, name: "lisa" },
  { value: 5, name: "jim" },
  { value: 6, name: "master" },
  { value: 1, name: "jim" },
   { value: 3, name: "" },
  { value: 2, name: "" },
];
var a = new Set();

var array2 = [];
for (i = 0; i < arr.length; i++) {
 if(!a.has(arr[i].name)){
   array2.push(arr[i]);
   a.add(arr[i].name);
 }
 else{
   var name = arr[i].name;
   for (j = 0; j < array2.length; j++) {
      if(array2[j].name == name ){
        array2[j].value += arr[i].value;
      }
  }
  
 
}
}
console.log(array2);

edited Feb 17 '20 at 13:05

answered Feb 17 '20 at 12:35

Manu Varghese

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Not giving desired output – Feb 17 '20 at 12:48
@Reactguy now please check – Manu Varghese Feb 17 '20 at 12:51
now it just removes the duplicates and not add values – Feb 17 '20 at 12:54
@Reactguy Sorry I didn't get it, can please explain in details ? – Manu Varghese Feb 17 '20 at 12:56
I want to add the values of the duplicates but the solution is only removing the duplicates na not adding the values – Feb 17 '20 at 12:58
@Reactguy please check now – Manu Varghese Feb 17 '20 at 13:06
Try this: let arrNew = arr.filter( (element, index) => index === arr.findIndex( i => i.name === element.name)) console.log(arrNew) – Yatin Gaikwad Feb 17 '20 at 13:12

Removing duplicates while adding their values in an array

1 Answers1