JSFiddle - React, Tailwind, and code Playground
JavaScript
var arr1 = [2, 4,9, 6];
var arr2 = [8,10, 15,10, 11, 12]
// 15, 12, 11, 10, 9
//console.log(arr1.concat(...arr2))
var arr3 = arr1.concat(arr2).sort((a, b)=> b-a)
var arr4 = [...new Set(arr3)];
//console.log(arr4)
console.log(arr4.slice(0, 5))