Underscore.js, remove duplicates in array of objects based on key value

Question

I have the following JS array:

var myArray = [{name:"Bob",b:"text2",c:true},
               {name:"Tom",b:"text2",c:true},
               {name:"Adam",b:"text2",c:true},
               {name:"Tom",b:"text2",c:true},
               {name:"Bob",b:"text2",c:true}
               ];

I want to eliminate the indexes with name value duplicates and recreate a new array, with distinct names, eg:

var mySubArray = [{name:"Bob",b:"text2",c:true},
                  {name:"Tom",b:"text2",c:true},
                  {name:"Adam",b:"text2",c:true},
                 ];

As you can see, I removed "Bob" and "Tom", leaving only 3 distinct names. Is this possible with Underscore? How?

I'm pretty sure this use case demands more than just _.filter — Dexygen
– Dexygen, Commented Mar 11, 2015 at 15:42
@GeorgeJempty: I tried _.filter but maybe I couldn't find a way to use it properly. — user1094081
– user1094081, Commented Mar 11, 2015 at 15:49

nikoshr · Accepted Answer · 2020-01-02 14:38:32Z

36

With Underscore, use _.uniq with a custom transformation, a function like _.property('name') would do nicely or just 'name', as @Gruff Bunny noted in the comments :

var mySubArray = _.uniq(myArray, 'name');

And a demo http://jsfiddle.net/nikoshr/02ugrbzr/

If you use Lodash and not Underscore, go with the example given by @Jacob van Lingen in the comments and use _.uniqBy:

var mySubArray = _.uniqBy(myArray, 'name')

edited Jan 2, 2020 at 14:38

answered Mar 11, 2015 at 15:50

nikoshr

33.4k34 gold badges94 silver badges112 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Gruff Bunny Over a year ago

You could just pass 'name' as the third parameter to _.uniq

Gruff Bunny Over a year ago

and remove the second parameter leaving just _.uniq(myArray, 'name') - just peeked at the underscore source

Jacob van Lingen Over a year ago

Note for lodash, it is: _.uniqBy(myArray, 'name')

Dexygen · Accepted Answer · 2015-03-11 16:38:35Z

3

The other answer is definitely best but here's another that's not much longer that also exposes you to more underscore method's, if you're interested in learning:

var mySubArray = []

_.each(_.uniq(_.pluck(myArray, 'name')), function(name) {
    mySubArray.push(_.findWhere(myArray, {name: name}));
})

edited Mar 11, 2015 at 16:38

answered Mar 11, 2015 at 16:14

Dexygen

12.6k13 gold badges87 silver badges154 bronze badges

Collectives™ on Stack Overflow

Underscore.js, remove duplicates in array of objects based on key value

2 Answers 2

3 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related