How to combine all unique element in any given array property from array of object into single array in javascript?

Question

I have below javascript array of object problem in which i have tag array property inside array of object. Tag array contain some value in each array of object. I wanted to get unique tag value from each array of object and combine into single array which will contain only unique tag.

const obj = [{
  name: "ABC",
  tag: ["abc", "xyz"]
}, {
  name: "USA",
  tag: ["abc", "suv"]
}, {
  name: "ABC",
  tag: ["pot", "xyz"]
}]

I need the unique tag item into single array as per below.

const unique = ["abc", "xyz", "suv", "pot"];

Does this answer your question? [Get all unique values in a JavaScript array (remove duplicates)](https://stackoverflow.com/questions/1960473/get-all-unique-values-in-a-javascript-array-remove-duplicates) — Nguyễn Văn Phong, Feb 25 '22 at 06:53
@James I added an answer. Did you get a chance to look into that. Hope it will work as per your expectation. — Rohìt Jíndal, Mar 01 '22 at 14:03

score 3 · Answer 1 · edited Feb 25 '22 at 06:44

3

You could use flatMap and Set

const obj = [
  { name: 'ABC', tag: ['abc', 'xyz'] },
  { name: 'USA', tag: ['abc', 'suv'] },
  { name: 'ABC', tag: ['pot', 'xyz'] },
]

const res = [...new Set(obj.flatMap(({tag}) => tag))];

console.log(res)

edited Feb 25 '22 at 06:44

Nguyễn Văn Phong

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answered Feb 25 '22 at 06:28

hgb123

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Hi hgb123, As @mplungjan said, you should use `Destructure` to make your code more concise. You can see [here](https://stackoverflow.com/a/67265714/9071943). I've just updated your answer accordingly. – Nguyễn Văn Phong Feb 25 '22 at 06:45

score 1 · Answer 2 · answered Feb 25 '22 at 06:28

1

A set will give you unique values:

const obj = [{
  name: "ABC",
  tag: ["abc", "xyz"]
}, {
  name: "USA",
  tag: ["abc", "suv"]
}, {
  name: "ABC",
  tag: ["pot", "xyz"]
}]

const unique = [...new Set(obj.flatMap(({tag}) => tag))];

console.log(unique)

answered Feb 25 '22 at 06:28

jsejcksn

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What makes your answer different from [@hgb123 's answer](https://stackoverflow.com/a/71261909/9071943)? – Nguyễn Văn Phong Feb 25 '22 at 06:54
@NguyễnVănPhong three identical answers were posted here within 30 seconds. It's just a coincidence. – A1exandr Belan Feb 25 '22 at 06:59
@NguyễnVănPhong Now that you've edited that user's answer, nothing in the code is different — my answer just includes more information in the form of links to documentation about the APIs and patterns used. – jsejcksn Feb 25 '22 at 07:11
Yeah, I see. @jsejcksn – Nguyễn Văn Phong Feb 25 '22 at 07:14

score 0 · Answer 3 · answered Feb 25 '22 at 08:17

You can use Set to filtered out the unique elements from an array.

Demo :

const obj = [{
  name: "ABC",
  tag: ["abc", "xyz"]
}, {
  name: "USA",
  tag: ["abc", "suv"]
}, {
  name: "ABC",
  tag: ["pot", "xyz"]
}];

let arr = [];

obj.forEach((item) => {
    arr.push(...item.tag)
})

console.log([...new Set(arr)]);

How to combine all unique element in any given array property from array of object into single array in javascript?

3 Answers3