Group JavaScript Object by group id-CodePudding

I have a JavaScript object as below

[{
  "id": "41e4858d-0478-4ffa-b39a-73db6f80c493",
  "price": 10,
  "class": "audi",
  "group": {
    "id": "group-1",
    "name": "Special",
  }
}, {
  "id": "d4ed6efe-3d95-4f19-9f34-16b1d62ee5f1",
  "price": 20,
  "class": "mercedess",
  "group": {
    "id": "group-1",
    "name": "Special",
  }
}, {
  "id": "a17a3671-09c4-411c-921f-a35705e86030",
  "price": 30,
  "class": "bmw",
  "group": {
    "id": "group-1",
    "name": "Special",
  }
}, {
  "id": "1bda1fe8-c326-46f4-851c-d06c686d1ebc",
  "price": 50,
  "class": "audi",
  "group": {
    "id": "group-2",
    "name": "Normal",
  }
}, {
  "id": "72300db9-c7f8-4bd6-af4a-f041e085bc6b",
  "price": 60,
  "class": "mercedess",
  "group": {
    "id": "group-2",
    "name": "Normal",
  }
}, {
  "id": "3fd3a054-3f97-4899-ba28-e1f22ba40bc8",
  "price": 70,
  "class": "bmw",
  "group": {
    "id": "group-2",
    "name": "Normal",
  }
}]

I'm trying to group these objects by group id. How can I achieve my desired output? Any help would be appreciated.

my desired output:

[
  {
    "id": "group-1",
    "name": "special",
    "mercedess": 20,
    "bmw":30,
    "auid":10
  },
  {
    "id": "group-2",
    "name": "normal",
    "mercedess": 60,
    "bmw":70,
    "auid":50
  }
]

thank you very much to those who helped

I tried to write it with javascript reduce function or lodash library, I couldn't get it to work.

CodePudding user response：

use reduce method:

const myArr = [{
  "id": "41e4858d-0478-4ffa-b39a-73db6f80c493",
  "price": 10,
  "class": "audi",
  "group": {
    "id": "group-1",
    "name": "Special",
  }
}, {
  "id": "d4ed6efe-3d95-4f19-9f34-16b1d62ee5f1",
  "price": 20,
  "class": "mercedess",
  "group": {
    "id": "group-1",
    "name": "Special",
  }
}, {
  "id": "a17a3671-09c4-411c-921f-a35705e86030",
  "price": 30,
  "class": "bmw",
  "group": {
    "id": "group-1",
    "name": "Special",
  }
}, {
  "id": "1bda1fe8-c326-46f4-851c-d06c686d1ebc",
  "price": 50,
  "class": "audi",
  "group": {
    "id": "group-2",
    "name": "Normal",
  }
}, {
  "id": "72300db9-c7f8-4bd6-af4a-f041e085bc6b",
  "price": 60,
  "class": "mercedess",
  "group": {
    "id": "group-2",
    "name": "Normal",
  }
}, {
  "id": "3fd3a054-3f97-4899-ba28-e1f22ba40bc8",
  "price": 70,
  "class": "bmw",
  "group": {
    "id": "group-2",
    "name": "Normal",
  }
}]

let results = myArr.reduce(function(results, newArr){
  (results[newArr.group.id] = results[newArr.group.id] || []).push(newArr);
    console.log(results);
},{})

less code and better result

CodePudding user response：

Let's call your object inputArr

You will first need to run a reduce on it to group it by groupId:

const intermediaryResult = inputArr.reduce((groups, current) => {
  groups[current.group.id] = {
    ...groups[current.group.id],
    id: current.group.id,
    name: current.group.name,
    [current.class]: current.price
  }
  return groups;
}, {})

Then, you'll be left with something like

{
  "group-1": {
    "id": "group-1",
    "name": "Special",
    "audi": 10,
    "mercedess": 20,
    "bmw": 30
  },
  "group-2": {
    "id": "group-2",
    "name": "Normal",
    "audi": 50,
    "mercedess": 60,
    "bmw": 70
  }
}

Which can easily be transformed in what you'd like with

Object.values(intermediaryResult)

All in all

Object.values(
  inputArr.reduce((groups, current) => {
    groups[current.group.id] = {
      ...groups[current.group.id],
      id: current.group.id,
      name: current.group.name,
      [current.class]: current.price
    }
    return groups;
  }, {})
)