Comparing two array of object javascript and remove values that are not equal

Question

I have two array of objects.

e = [{uniqueId:'',active:'a',qId:10},{uniqueId:'',active:'a',qId:11}]
f = [{uniqueId:50,active:'a',qId:10},{uniqueId:51,active:'a',qId:11},{uniqueId:52,active:'a',qId:13}]

I want to compare these objects and my final result will be like

result = [{uniqueId:50,active:'a',qId:10},{uniqueId:51,active:'a',qId:11}]

I tried

let result = e.filter(o1 => f.some(o2 => o1.qId != o2.qId));

But am getting

[{uniqueId:50,active:'a',qId:10},{uniqueId:51,active:'a',qId:11},{uniqueId:52,active:'a',qId:13}]

How to achieve the desired output?

please add what you mean by "... values that are not equal" — Nina Scholz
– Nina Scholz, Commented Jul 31, 2018 at 7:28
Compare the two array of objects using 'qId', if qId is present in one object and not in the other, i don't want that object in result — karthi
– karthi, Commented Jul 31, 2018 at 7:30

CertainPerformance · Accepted Answer · 2018-07-31 07:31:00Z

2

It looks like you should be filtering f, not e, because the result shows values from f, not from e.

For the least complexity, turn the e array's qIds into a Set for quick lookup first. (Sets have O(1) lookup time, compared to O(N) complexity for .some)

const e = [{uniqueId:'',active:'a',qId:10},{uniqueId:'',active:'a',qId:11}]
const f = [{uniqueId:50,active:'a',qId:10},{uniqueId:51,active:'a',qId:11},{uniqueId:52,active:'a',qId:13}]

const qIds = new Set(e.map(({ qId }) => qId));
console.log(f.filter(({ qId }) => qIds.has(qId)));

answered Jul 31, 2018 at 7:31

CertainPerformance

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Comments

Beginner · Accepted Answer · 2018-07-31 07:38:29Z

2

i hope you need to compare on qId..

let e = [{uniqueId:'',active:'a',qId:10},{uniqueId:'',active:'a',qId:11}]
let f = [{uniqueId:50,active:'a',qId:10},{uniqueId:51,active:'a',qId:11},{uniqueId:52,active:'a',qId:13}]
let res = [];
f.forEach(fo => {
  e.forEach(eo => {
    if(fo.qId === eo.qId){
       res.push(fo)
    }
  })
})

console.log(res)

answered Jul 31, 2018 at 7:38

Beginner

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Comments

Ankit Agarwal · Accepted Answer · 2018-07-31 07:33:41Z

1

You can use Array.filter() and Array.some() in combination to get that result:

e = [{uniqueId:'',active:'a',qId:10},{uniqueId:'',active:'a',qId:11}]
f = [{uniqueId:50,active:'a',qId:10},{uniqueId:51,active:'a',qId:11},{uniqueId:52,active:'a',qId:13}];
var res = f.filter(fItem => e.some(({qId}) => fItem.qId === qId));
console.log(res);

answered Jul 31, 2018 at 7:33

Ankit Agarwal

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Comments

Nina Scholz · Accepted Answer · 2018-07-31 07:31:47Z

0

You could check if array e has the same qId value for filtering f.

var e = [{ uniqueId: '', active: 'a', qId: 10 }, { uniqueId: '', active: 'a', qId: 11 }],
    f = [{ uniqueId: 50, active: 'a', qId: 10 }, { uniqueId: 51, active: 'a', qId: 11 }, { uniqueId: 52, active: 'a', qId: 13 }],
    result = f.filter(({ qId }) => e.some(o => o.qId === qId));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Jul 31, 2018 at 7:31

Nina Scholz

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2 Comments

TMA Over a year ago

Hi @NinaScholz; i am doing the same thing with the just one condition change about not equal to !== but that is not working in my case. So is there any other method to work with the not equal to condition ? Check my live example over here: playcode.io/586815

Nina Scholz Over a year ago

@aananddham, please ask a new question, if necessary. the comment section is not to answer another question.

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