Concat two nodelists

Question

I am trying to concat two nodelists using

var ul   = document.querySelector(\"ul\");
var down = document.getElementsByClassName(\"mobile\")[0];
var ul_child = Ar         


        

Answer 1

Set() ensures items are unique and the ES6 Spread operator makes it neat & tidy:

var elems = new Set([
    ...document.querySelectorAll(query1),
    ...document.querySelectorAll(query2)
]);