Tips for accessing a nested object field in JavaScript

Question

Tips for accessing a nested object field in JavaScript

Trying to access the field names of an object nested within another object is causing an issue. In this scenario, attempting to loop through the user object was unsuccessful as an error stating

Object is possibly 'null' or 'undefined'

was encountered.

18 console.log(message[0].message.id);

{ 
  message: {
    id: '0301939f-59b5-45f0-bc24-89a4d6840579',
    text: 'Everyone is here with the intention to improve.',
    html: '<p>Everyone is here with the intention to improve.</p>\n',
    type: 'regular',
    user: [Object],
    attachments: [Array],
    latest_reactions: [],
    own_reactions: [],
    reaction_counts: null,
    reaction_scores: {},
    reply_count: 0,
    cid: 'messaging:3',
    created_at: '2021-07-08T20:23:02.354861Z',
    updated_at: '2021-07-08T20:23:02.354861Z',
    shadowed: false,
    mentioned_users: [],
    silent: false,
    pinned: false,
    pinned_at: null,
    pinned_by: null,
    pin_expires: null,
    channel: [Object],
    title: 'Welcome to your pod <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6105590b101b191b191159211113081700150413040d00184f0011110d0408054f020e0c">[email protected]</a>' 
  } 
}]
3

User Object:

{ 
  id: 'masterHealthBot',
  role: 'admin',
  created_at: '2021-06-21T15:12:20.226915Z',
  updated_at: '2021-07-08T21:11:34.32916Z',
  banned: false,
  online: false,
  name: 'MasterHealth Bot' 
}
3

const message = response.results.map(({ message }) => message.user);

console.log(message[0].id); // not working
console.log(message.map(({user}) => user.id)) gives a user undefined error

Any assistance on resolving this issue would be greatly valued. Thank you for your time.

typescript

Answer 1

Answer №1

I'm a bit confused about what you're trying to achieve here. If the user is nested within the message, why not simply use message.user to access the User object? You can utilize the map method, along with [0] (index selector) for arrays.

UPDATE: It appears that user is actually an array of objects.

Here's one way to approach this:

const message = {
  id: 'messageId1234',
  user: [{
    id: 'masterHealthBot',

  },
  {
    id: 'masterHealthBot2',

  }]
}
const users = message?.user;

users.map(user => console.log(user.id))

Answer 2

I'm a bit confused about what you're trying to achieve here. If the user is nested within the message, why not simply use message.user to access the User object? You can utilize the map method, along with [0] (index selector) for arrays.

UPDATE: It appears that user is actually an array of objects.

Here's one way to approach this:

const message = {
  id: 'messageId1234',
  user: [{
    id: 'masterHealthBot',

  },
  {
    id: 'masterHealthBot2',

  }]
}
const users = message?.user;

users.map(user => console.log(user.id))

Answer 3

Answer №2

If you are looking to retrieve a single user id, you can simply access it with messages[0].user[0].id.

To obtain all the user ids, you can utilize the following code snippet:

const messages = response.results;
const allUserIds = messages.flatMap((message) => {
  return message.user.map((user) => user.id);
});
console.log(allUserIds);

Alternatively, if Array.prototype.flatMap is not available, you can achieve the same result using Array.prototype.reduce:

const messages = response.results;
const allUserIds = messages.reduce((result, message) => {
  const messageUsersIds = message.user.map((user) => user.id);
  return [...result, ...messageUsersIds];
}, []);
console.log(allUserIds);

Answer 4

If you are looking to retrieve a single user id, you can simply access it with messages[0].user[0].id.

To obtain all the user ids, you can utilize the following code snippet:

const messages = response.results;
const allUserIds = messages.flatMap((message) => {
  return message.user.map((user) => user.id);
});
console.log(allUserIds);

Alternatively, if Array.prototype.flatMap is not available, you can achieve the same result using Array.prototype.reduce:

const messages = response.results;
const allUserIds = messages.reduce((result, message) => {
  const messageUsersIds = message.user.map((user) => user.id);
  return [...result, ...messageUsersIds];
}, []);
console.log(allUserIds);

Tips for accessing a nested object field in JavaScript

Answer №1

Answer №2

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