javascript: object destructuring

Question

I have a this object:

{
  "userAuth": {
    "id": 1,
    "uuid": "e30fa23a-bfe4-495e-b6ac-79d49cb9a5a5",
    "login": 12,
    "password": "",
    "role": "WORKER_ROLE",
    "user": {
      "id": 2,
      "uuid": "f0ca9c33-a5b7-48c1-9956-1d4d372475ec",
      "firstName": "Adrian",
      "lastName": "Pietrzak",
      "email": "[email protected]",
      "phone": null,
      "avatar": null,
      "street": "string",
      "city": "string",
      "state": "string",
      "zip": "string",
      "createdAt": "2019-10-12",
      "lastLogin": "2019-11-29T20:03:17.000Z",
      "lastLogout": null
    }
  },
  "iat": 1570996289
}

and I would like to object destructing to this:

{
    "role": "WORKER_ROLE",
    "uuid": "f0ca9c33-a5b7-48c1-9956-1d4d372475ec"
}

how to make data object destructuring out of it? I try to this:

const { role, user.uuid } = userAuth;

const result = {role: userAuth.role, uuid: userAuth.user.uuid}; <--- isn't it much more readable in this very case? — zerkms
– zerkms, Commented Oct 13, 2019 at 20:39

Bergi · Accepted Answer · 2019-10-13 20:05:49Z

4

Destructuring doesn't build an object. You first need to destructure into local variables:

const { role, user: { uuid } } = userAuth;

then build the result from them:

const result = { role, uuid };

Alternatively, use a single statement without any destructuring:

const result = { role: userAuth.role, uuid: userAuth.user.uuid };

edited Oct 13, 2019 at 20:05

answered Oct 13, 2019 at 20:00

Bergi

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5 Comments

reactdto Over a year ago

I can this: const [uuid, role] = [userAuth.user.uuid, userAuth]; but I think that your result is better

Bergi Over a year ago

@reactdto Sure, you can write it out to const uuid = userAuth.user.uuid, role = userAuth.role; (no need for arrays), but the OP asked for destructuring

zerkms Over a year ago

"You first need to destructure into local variables" --- or one could assign to a new object during destructuring: const result = {}; ({ role: result.role } = userAuth );

Bergi Over a year ago

@zerkms Yeah, but that's much uglier than all the alternatives :-)

zerkms Over a year ago

@Bergi in this particular case any destructuring is ugly and pointless :-). My idea was that if you wanted to cover destructuring features (given that "but the OP asked for destructuring") then adding that another sample would make it more complete :shrug:

Kamil Naja · Accepted Answer · 2019-10-13 20:23:37Z

0

This is sample answer. I think, that you should call userAuth property of your object.

const obj = {
      "userAuth": {
        "id": 1,
        "uuid": "e30fa23a-bfe4-495e-b6ac-79d49cb9a5a5",
        "login": 12,
        "password": "",
        "role": "WORKER_ROLE",
        "user": {
          "id": 2,
          "uuid": "f0ca9c33-a5b7-48c1-9956-1d4d372475ec",
          "firstName": "Adrian",
          "lastName": "Pietrzak",
          "email": "[email protected]",
          "phone": null,
          "avatar": null,
          "street": "string",
          "city": "string",
          "state": "string",
          "zip": "string",
          "createdAt": "2019-10-12",
          "lastLogin": "2019-11-29T20:03:17.000Z",
          "lastLogout": null
        }
      },
      "iat": 1570996289
    }

const {role, user: {uuid} } = obj.userAuth;

console.log({role: role, uuid: uuid}) // this gives output, that you expect

edited Oct 13, 2019 at 20:23

answered Oct 13, 2019 at 20:11

Kamil Naja

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3 Comments

reactdto Over a year ago

Nie potrzebuję uuid z obiektu userAuth, tylko z user

reactdto Over a year ago

już ktoś wyżej napisał to samo, ale dam Ci najlepszą odpowiedź bo widzę że dbasz o konto. Dzięki! ; )

RegarBoy Over a year ago

Last line could be better changed to this: console.log({role, uuid}) - no need to repeat yourself.

Taki · Accepted Answer · 2019-10-13 20:10:52Z

You can have an IIFE that destructures the object and returns the destructured properties :

const data = {
  "userAuth": {
    "id": 1,
    "uuid": "e30fa23a-bfe4-495e-b6ac-79d49cb9a5a5",
    "login": 12,
    "password": "",
    "role": "WORKER_ROLE",
    "user": {
      "id": 2,
      "uuid": "f0ca9c33-a5b7-48c1-9956-1d4d372475ec",
      "firstName": "Adrian",
      "lastName": "Pietrzak",
      "email": "[email protected]",
      "phone": null,
      "avatar": null,
      "street": "string",
      "city": "string",
      "state": "string",
      "zip": "string",
      "createdAt": "2019-10-12",
      "lastLogin": "2019-11-29T20:03:17.000Z",
      "lastLogout": null
    }
  },
  "iat": 1570996289
}


const result = (({ role, user: { uuid } }) => ({role, uuid}))(data.userAuth);

console.log(result);

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