JSFiddle - React, Tailwind, and code Playground

HTML

<label><input type="checkbox" class="btn" value="italy"/>italy</label>
<label><input type="checkbox" class="btn" value="usa"/>usa</label>
<label><input type="checkbox" class="btn" value="france"/>france</label>
<label><input type="checkbox" class="btn" value="spain"/>spain</label>

JavaScript

var arr = ["rome","new-york","paris","madrid"];


const checked = [...document.querySelectorAll('.btn:checked')].map(n => n.value);
let  filtered = arr.filter(n => checked.includes(n));