Check if two arrays have non-repeating identical elements

Question

I want to check if two arrays have non-repeating identical elements.

const first = [1,2,3,4]
const second = [1,2]

const result = second.every(element => first.includes(element))
//Result: true

But this code doesn't work with duplicated elements. For example:

const first = [1,2,3,4]
const second = [3,3]

const result = second.every(element => first.includes(element))
//Result: true //MUST BE false

How can I solve it? Please help!

Check if an array has duplicate values: https://stackoverflow.com/questions/19655975/check-if-an-array-contains-duplicate-values — kelsny, Sep 06 '22 at 20:12
What is "non-repeating identical elements" ? to me 1,2,3,4 don't look identical to 1,2 — Alejandro Montilla, Sep 06 '22 at 20:16
Alejandro, I wrote a question with google translate, maybe in the print) I mean in array [1,2,3,4] has values [1,2], bun in [1,2,3,4] hasn't values [3,3] — Baglan Abdirassil, Sep 06 '22 at 20:29

score 2 · Accepted Answer · answered Sep 06 '22 at 20:15

2

const result = second.every(element => first.includes(element) && second.indexOf(element) !== second.lastIndexOf(element))

answered Sep 06 '22 at 20:15

adsy

This code works for me! Thank you! – Baglan Abdirassil Sep 06 '22 at 20:24
@BaglanAbdirassil Would you mind marking as accepted :) – adsy Sep 06 '22 at 21:43

1 Answers1