js union arrays

let a = [34, 35, 45, 48, 49];
let b = [48, 55];
let union = [...new Set([...a, ...b])];
console.log(union);

var hege = ["Cecilie", "Lone"];

var stale = ["Emil", "Tobias", "Linus"];

var kai = ["Robin"];

var children = hege.concat(stale, kai);