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"];

Answer 1

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)

Answer 2

A set will give you unique values:

• Set
• Array.prototype.flatMap()
• Spread syntax (...)
• Unpacking properties from objects passed as a function parameter

 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)

Answer 3

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)]);