How to access dynamic key values of a JSON object in node.js?

Question

I'm facing issues in retrieving the JSON data.

Here am getting the JSON with dynamic keys. And I need to access that dynamic key's values. The dynamic key is coming from URL and am fetching that key's data from DB.

Here is my sample data.

let roleData = [
  {
    "assetCategory": {
       "canCreate": false,
       "canView": false,
       "canUpdate": false,
       "canDelete": false,
       "isMenu": false,
       "parent": "settings"
     }
  }
]

In the above JSON, I've got assetCategory object. But this value is completely dynamic. I might get other values too in the place of assetCategory. So without knowing this key, it's getting difficult for me to access the data.

Is there any way to access this dynamic object?

Arpan Kc · Accepted Answer · 2020-04-08 09:41:05Z

4

let data = [
  {
    "assetCategory": {
       "canCreate": false,
       "canView": false,
       "canUpdate": false,
       "canDelete": false,
       "isMenu": false,
       "parent": "settings"
     }
  }
]


let unknownNames = data.map( item => Object.keys(item)) // returns ['assetCategory']
//Returns array of all the unknown names
console.log(unknownNames);

edited Apr 8, 2020 at 9:41

answered Apr 8, 2020 at 9:27

Arpan Kc

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7 Comments

Aravind Over a year ago

Thanks. But when I use the above solution, am getting this as the result in console [ [ '$__', 'isNew', 'errors', '_doc', '$locals', '$op', '$init' ] ]

Arpan Kc Over a year ago

This seems to work. repl.it/repls/IcyBubblyStructures Maybe try using a different variable name besides 'data'

Aravind Over a year ago

It's working in onine editors. But not in my code. Still getting, $__

Aravind Over a year ago

This is what am giving as the input to the code you have commented

Aravind Over a year ago

[ { assetCategory:      { canCreate: false,        canView: false,        canUpdate: false,        canDelete: false,        isMenu: false,        parent: 'settings' } } ]

|

pierreavn · Accepted Answer · 2020-04-08 09:24:36Z

4

You should use Object.keys(...) : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys

For example:

const a = [
  {
    "assetCategory": {
       "canCreate": false,
       "canView": false,
       "canUpdate": false,
       "canDelete": false,
       "isMenu": false,
       "parent": "settings"
     }
  }
];

const name = Object.keys(a[0])[0]; // --> "assetCategory"
console.log(a[0][name]) // --> {"canCreate": false, ...}

answered Apr 8, 2020 at 9:24

pierreavn

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1 Comment

Aravind Over a year ago

When I use your answer, am getting this, $__. What does this mean?

satanTime · Accepted Answer · 2020-04-08 09:25:03Z

1

you can get all keys by Object.keys(data[0].assetCategory). and then data[0].assetCategory[varWithKeyValue] or if it's dynamic data[0].assetCategory['can' + 'Create']

answered Apr 8, 2020 at 9:25

satanTime

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3 Comments

Aravind Over a year ago

No, I want to get assetCategory object itself. But the problem is, assetCategory is a dynamic key. In that place I might get assetStatus and I should get assetStatus 's object too

satanTime Over a year ago

then you can do the same with Object.keys(data[0]).

satanTime Over a year ago

in case if you want to get only keys of the object the modern way is Object.getOwnPropertyNames(data[0]).

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