JSFiddle - React, Tailwind, and code Playground

by Sergei Marochkin

JavaScript

const elements = [1,2,3,2,1,5,6,5,5,5, 534, 534, 43534,534, 3534543];


const items = new Set(elements);

const duplicates = _.filter(arr, (val, i, iteratee) => _.includes(iteratee, val, i + 1));


console.log(duplicates);