найти союз массивов
let union = [...arrA, ...arrB];
Ngoc Chau
let union = [...arrA, ...arrB];// union of two arrays javascript (duplicate)
const union = (a, b) => Array.from(new Set([...a, ...b]));
console.log(union([1, 2, 3], [4, 3, 2]))
// output
// [1, 2, 3, 4]1 2 3 4 5