Create unique array from arrays (Multiple)

Question

Am trying the following

Input:
myarray1=['Tag A','Tag B','Tag C']
myarray2=['Tag B','Tag C']
myarray3=['Tag A','Tag D']

Output:

outputArray=['Tag A','Tag B','Tag C','Tag D']

The output array should conatin the unique values from the input arrays.

Am trying this in typescript but not able to find the unique values from input array. Any suggestions how to achieve this in optimal way

In that question duplicates were removed from single array, here the question is from multiple arrays — RBG, Dec 20 '18 at 16:42
Possible duplicate of [How to merge two arrays in JavaScript and de-duplicate items](https://stackoverflow.com/questions/1584370/how-to-merge-two-arrays-in-javascript-and-de-duplicate-items) and [Getting a union of two arrays in JavaScript](https://stackoverflow.com/questions/3629817) — adiga, Dec 20 '18 at 16:47
[How much research effort is expected of Stack Overflow users?](https://meta.stackoverflow.com/a/261593/3082296) — adiga, Dec 20 '18 at 16:50

score 3 · Accepted Answer · answered Dec 20 '18 at 15:52

3

Pass the merged arrays into a Set and spread that set into results array

myarray1=['Tag A','Tag B','Tag C']
myarray2=['Tag B','Tag C']
myarray3=['Tag A','Tag D']

const uniques = [...new Set(myarray1.concat(myarray2,myarray3))]

console.log(uniques)

answered Dec 20 '18 at 15:52

charlietfl

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A l w a y s S u n n y · Answer 2 · 2018-12-20T15:56:34.843

2

You can easily do it with ES6 Spread and Set

myarray1=['Tag A','Tag B','Tag C']
myarray2=['Tag B','Tag C']
myarray3=['Tag A','Tag D']
const uniqueArr = [...new Set([...myarray1,...myarray1,...myarray3])];
console.log(uniqueArr)

edited Dec 20 '18 at 15:56

answered Dec 20 '18 at 15:53

A l w a y s S u n n y

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where do you use `destructuring` here? – quirimmo Dec 20 '18 at 15:56
@quirimmo sorry my bad. Just used wrong wording :( – A l w a y s S u n n y Dec 20 '18 at 15:59

score 1 · Answer 3 · 2018-12-20T16:01:43.607

Very simple, only using array functions, first you conctainate all of the arrays, then you use the fitler function to simply ensure that there's only ever unique values.

const myarray1 = ['Tag A', 'Tag B', 'Tag C'],
  myarray2 = ['Tag B', 'Tag C'],
  myarray3 = ['Tag A', 'Tag D'];

const mergedArray = Array.concat(myarray1, myarray2, myarray3).filter((s, i, array) => array.indexOf(s) === i);
console.log(mergedArray);

score 1 · Answer 4 · answered Dec 20 '18 at 16:06

1

You can do it with reduce Set and spread operator.

let arr1=['Tag A','Tag B','Tag C']
let arr2=['Tag B','Tag C']
let arr3=['Tag A','Tag D']

let arr = [arr1,arr2,arr3]
let op = [...new Set( arr.reduce((o,c)=>o.concat(c),[]))];

console.log(op);

answered Dec 20 '18 at 16:06

Code Maniac

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Create unique array from arrays (Multiple)

4 Answers4