Lodash / javascript : Compare two collections and return the differences

Question

I have two arrays of objects:

Elements of my tables are not primitive value, but complex objects.

array1 = [obj1,obj2,obj3,obj4]
array2 = [obj5,obj5,obj6,obj7]

I would like to compare two arrays and see if the elements of array2 are already present in array1 then create a new array of the difference.

Any suggestions?

so this was marked duplicate by 6 people? do those 6 people even know the difference between an array of primitives and an array of complex objects? — Emobe, Mar 13 '19 at 14:58
I think lodash _.differenceBy(https://lodash.com/docs/4.17.15#differenceBy) could help. — Shivam Kubde, Feb 28 '20 at 04:47

score 63 · Accepted Answer · edited Feb 24 '21 at 19:56

63

var presents = _.intersectionWith(array1, array2, _.isEqual);
var dif = _.differenceWith(array1, array2, _.isEqual);

_.differenceWith is only available since 4.0.0 lodash version

edited Feb 24 '21 at 19:56

Community

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answered Nov 17 '16 at 13:33

stasovlas

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_.differenceWith is only available since 4.0.0 lodash version – Siva Kannan Jan 29 '18 at 08:10
did you see he ask about :::: arrays of objects array1 = [obj1,obj2,obj3,obj4] array2 = [obj5,obj5,obj6,obj7] – Justin Meskan Jul 16 '21 at 02:53

Alex Bykov · Answer 2 · 2016-11-17T13:43:21.490

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ES6 This will be enough:

array2.filter(e => !array1.includes(e));

without includes

array2.filter(e=> array1.indexOf(e) < 0);

Plunker for you

edited Nov 17 '16 at 13:43

answered Nov 17 '16 at 13:31

Alex Bykov

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can't use your solution since i'am using angular 2 with typescript, includes return an error – Nacim Idjakirene Nov 17 '16 at 13:39
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this is NOT enough. you are using primitive values in the plunkr, OP is not – Emobe Mar 13 '19 at 14:59

score 7 · Answer 3 · answered Nov 17 '16 at 13:35

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_.difference gives you only the elements that are in the 1st array but not in the second one, nothing about the elements on the array 2 that are not in the array 1.

Is this what you want to achieve?

answered Nov 17 '16 at 13:35

Matteo Bombelli

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yes this is what i'am trying to achieve, but when i use _difference in the case that my two array are idantical i have array1 as output ! is it normal ? – Nacim Idjakirene Nov 17 '16 at 13:43
no... should send you [] (I've tested it now on chrome console in lodash docs...). are you using nodejs or a web browser? – Matteo Bombelli Nov 17 '16 at 17:45
yeah finally it works fine, it was an error made by me . thx for your help – Nacim Idjakirene Nov 17 '16 at 20:59

Lodash / javascript : Compare two collections and return the differences

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