CODEWITHSUNDEEP
javascriptnestedlodash
Dane
Dane

Reputation: 9542

Plucking keys of nested objects with Lodash

I have a structure like this:

      areas = {
        'sample-id': {
          title: 'Area 1',
          type: 'outdoor',
          boundaries: [
            'fm-86071.92984676428', 'fm-33663.81255808968',
            'fm-22124.724922206497', 'fm-98002.82095021005'
          ]
        },
        'sample-id-2': {
          title: 'Area 2',
          type: 'meetingroom',
          boundaries: [
            'fm-39517.47084731459', 'fm-79087.74683350614',
            'fm-39153.28644344014', 'fm-38873.63204123109',
            'fm-67952.07827771583', 'fm-53210.58304837807',
          ]
        }
      };

I need to obtain an array consisting of all title keys of each area, i.e., required output = ['Area 1', 'Area 2'].
I found that _.pluck has been removed in favor of _.map, but using

_.map(areas, 'title')

..needs areas to be an array.
I also think that converting the object into an array using _.values and then using _.map ought to work, but is there any direct or preferred way ?
EDIT: I would also like to retain the order of keys
EDIT 2: Ok I forgot that there is NO ORDER for keys in objects, so leave that, I guess I'll use Array.prototype.sort()

Upvotes: 0

Views: 7972

Answers (3)

Ori Drori
Ori Drori

Reputation: 191976

Lodash's _.map() works on objects as well:

var areas = {"sample-id":{"title":"Area 1","type":"outdoor","boundaries":["fm-86071.92984676428","fm-33663.81255808968","fm-22124.724922206497","fm-98002.82095021005"]},"sample-id-2":{"title":"Area 2","type":"meetingroom","boundaries":["fm-39517.47084731459","fm-79087.74683350614","fm-39153.28644344014","fm-38873.63204123109","fm-67952.07827771583","fm-53210.58304837807"]}};

var result = _.map(areas, 'title');

console.log(result);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

Upvotes: 1

Prasanna
Prasanna

Reputation: 4636

You can use Object.values().

areas = {
   'sample-id': {
     title: 'Area 1',
     type: 'outdoor',
     boundaries: [
       'fm-86071.92984676428', 'fm-33663.81255808968',
       'fm-22124.724922206497', 'fm-98002.82095021005'
     ]
   },
   'sample-id-2': {
     title: 'Area 2',
     type: 'meetingroom',
     boundaries: [
       'fm-39517.47084731459', 'fm-79087.74683350614',
       'fm-39153.28644344014', 'fm-38873.63204123109',
       'fm-67952.07827771583', 'fm-53210.58304837807',
     ]
   }
};
      
let returnValue = Object.values(areas).map(value => value.title)
console.log(returnValue)

Upvotes: 0

klugjo
klugjo

Reputation: 20885

In this case I use

Object.keys(areas).map(k => areas[k].title)

Upvotes: 1

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