JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="main">
  <li>
    <span>Fiat</span>
    <ul>
      <li>Punto</li>
      <li>Croma</li>
    </ul>
  </li>
  <li>
    <span>Ford</span>
    <ul>
      <li>Focus</li>
      <li>Fiesta</li>
      <li>bla bla...</li>
    </ul>
  </li>
</ul>

JavaScript

var arr = [];
$("#main>li").each(function() {
    var elem = {
        brand: $(this).find(">span:first").text(),
        models: []
    };
    $(this).find(">ul>li").each(function() {
        elem.models.push($(this).text());
    });
    arr.push(elem);
});
alert(arr[0].brand);
alert(arr[1].models[1]);