StackOverflow dúvida

HTML

<div class="container">
      <main class="content">
        <div class="selects-area">
          <select name="mapSelector" id="mapSelector">
            <option value="" disabled selected>Selecione um mapa</option>
            <option value="0">Dust II</option>
            <option value="1">Mirage</option>
            <option value="2">Cache</option>
            <!-- <option value="...">___</option> -->
          </select>
        </div>

        <button class="play" onclick="basicLogic();">Jogar</button>
      </main>
    </div>

JavaScript

const maps = [
  {
    mapName: "dust ii",
    positions: [
      {
        posicao: "fundo",
        posicaoImg: "#",
      },
      {
        posicao: "escuro baixo",
        posicaoImg: "#",
      },
      {
        posicao: "base tr",
        posicaoImg: "#",
      },
      {
        posicao: "base ct",
        posicaoImg: "#",
      },
    ],
  },
  {
    mapName: "mirage",
    positions: [
      {
        posicao: "fundomirage",
        posicaoImg: "#",
      },
      {
        posicao: "escuro baixomirage",
        posicaoImg: "#",
      },
    ],
  },
];

let selectElementMap = document.getElementById("mapSelector");

const desordenar = (arr) => {
  const copia = [...arr];

  for (let i = copia.length - 1; i > 0; i--) {
    let j = Math.floor(Math.random() * (i + 1));
    [copia[i], copia[j]] = [copia[j], copia[i]];
  }

  return copia;
};

function basicLogic() {
  let valueSelectedMap =
    selectElementMap.options[selectElementMap.selectedIndex].value;

  const desordenado = desordenar(maps[valueSelectedMap].positions); // o array que será randomizado com base no <select> do usuario
  console.log(desordenado.shift()); // Pega o primeiro da lista
}