Remove duplicate items in objects array with lodash.js

Question

I'm trying to remove duplicate items using lodash.js but I can't make it works properly.

This is the structure of an object in the array:

{
   label: 'tagA',
   value: 1
}

So let say I have this array:

var objectsArray = [
  {
    label: 'tagA',
    value: 1
  },
  {
    label: 'tagB',
    value: 2
  },
  {
    label: 'tagC',
    value: 3
  },
  {
    label: 'tagB',
    value: 4
  },
  {
    label: 'tagB',
    value: 5
  },
];

I made this piece of code with _.uniqBy() function from lodash.js to try to remove the elements of array with the same labels, but it dosn't work as I expected:

    var uniq = _.uniqBy(objectsArray, function(o){
        return o.label;
    });

I based on some sample found here and there and lodash documentation of course but I have a lack of knowledge in this regard so any help it will super appreciate it.

Thanks.

it doesn't work as expected How do you expect it to work, and how does it work? — user663031
– user663031, Commented May 21, 2016 at 15:18

flppv · Accepted Answer · 2016-05-21 15:11:18Z

11

Make sure that you use proper namings, that code works for me:

    var arr = [
                {
                  label: 'tagA',
                  value: 1
                },
                {
                  label: 'tagB',
                  value: 2
                },
                {
                  label: 'tagC',
                  value: 3
                },
                {
                  label: 'tagB',
                  value: 4
                },
                {
                  label: 'tagB',
                  value: 5
                },
              ];

    var uniq = _.uniqBy(arr, function(o){
        return o.label;
    });

    console.log(uniq); // >> Returned an array with first 3 objects from array arr

answered May 21, 2016 at 15:11

flppv

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6 Comments

flppv Over a year ago

I think he missed the array name in the first .uniqBy() argument

user663031 Over a year ago

No, he passed objectsArray.

flppv Over a year ago

I see. But I don't see if he declared it, I see only unnamed array above.

user663031 Over a year ago

It's a safe assumption that he did. If you think he might not have, you should leave a comment confirming that.

flppv Over a year ago

@torazaburo that's just only way to fail here, or maybe he forgot to import lib

|

Rosmarine Popcorn · Accepted Answer · 2016-05-21 15:22:54Z

2

If you want to make sure you can use uniqWith();

This works for me

var data = [
  {
    label: 'tagA',
    value: 1
  },
  {
    label: 'tagB',
    value: 2
  },
  {
    label: 'tagC',
    value: 3
  },
  {
    label: 'tagB',
    value: 4
  },
  {
    label: 'tagB',
    value: 5
  },
];

var filtered = _.uniqWith(data, function(first, second){

    return first.label === second.label
});

edited May 21, 2016 at 15:22

answered May 21, 2016 at 15:14

Rosmarine Popcorn

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Comments

Samvel Petrosov · Accepted Answer · 2016-05-21 15:12:11Z

0

I think the second example is just what you need uniqBy:

// The `_.property` iteratee shorthand.
_.uniqBy([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
// → [{ 'x': 1 }, { 'x': 2 }]

answered May 21, 2016 at 15:12

Samvel Petrosov

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1 Comment

Yonirt Over a year ago

Thanks for your effort I really appreciate it.

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