How to create arrays based on values from another array?

Question

I have an array of objects. All objects have the same properties. I'm trying to find a way to create new arrays for each of the common id's. This is my array: `

var array = 
  [
    {
      id: "BG",
      qty: 100
    }, 
    {
      id: "BG",
      qty: 35
    }, 
    {
      id: "JP",
      qty: 75
    },
    {
      id: "JP",
      qty: 50
    }
 ];

`

I wan it to create arrays based on the id property. Based on the above array, I'm expecting 2 arrays for BG and JP.

I tried this but it creates an array with just the 2 id's const uniqueId = [...new Set(array.map(array => array.id))];

What I want my result to be is:

[{
  id: "BG",
  qty: 100
}, 
{
  id: "BG",
  qty: 35
}]
[{
      id: "JP",
      qty: 75
    },
    {
      id: "JP",
      qty: 50
    }
 ]

Please edit your expected output so it's valid JavaScript. It's kind of hard to figure out exactly what you want. — code
– code, Commented Nov 15, 2022 at 21:04
array.reduce((obj, cur) => (obj[cur.id] = [...(obj[cur.id] || []), cur], obj), {})? — code
– code, Commented Nov 15, 2022 at 21:06
If you can use lodash, groupBy would do what you want here. _.groupBy(array, 'id') returns { BG: [{ id: 'BG', qty: 100 }, { id: 'BG', qty: 35 }], JP: [{ id: 'JP', qty: 75 }, { id: 'JP', qty: 50 }] } — romellem
– romellem, Commented Nov 15, 2022 at 21:07

Andres Carrasquilla · Accepted Answer · 2022-11-15 21:15:55Z

1

This can help you

var results = array.reduce(function(results, org) {
    (results[org.id] = results[org.id] || []).push(org);
    return results;
}, {})

I took it of: Group by Object ID's in Javascript

answered Nov 15, 2022 at 21:15

Andres Carrasquilla

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2 Comments

iyhc Over a year ago

Can use Object.values(results) at the end if OP wants multiple arrays instead of single object

Community Over a year ago

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