Как добавить в массив элемент, переключаемый как активный?

 
 var controller = (function () {
  var ctrlAddItem = function (event) {
    console.info("It worked, pressed id  = " + event.target.id);
    event.target.classList.toggle("active");
 };

  document.querySelectorAll(".btn_reservas").forEach(function () {
    this.addEventListener("click", ctrlAddItem);
  });

  document.addEventListener("keypress", function (event) {
    if (event.keyCode === 13 || event.which === 13) {
      ctrlAddItem();
    }
  });  

var sum = 0;
  var x = document.getElementsByClassName("btn_reservas");
  // var x = document.getElementsByClassName("btn_reservas.active");
  var numbers = [];
  for (i=0; i < x.length; i++){
    x[i].id;
    numbers.push(', ' + x[i].id);
  }

  numbers.forEach(myFunction);

  function myFunction(item) {
    sum += item;
    document.getElementById("demo").innerHTML = sum;
  }
})();

body {
    background-color: #ffffff;
  }
  
  h1 {
    color: #999999;
    align-content: center;
    padding-left: 400px;
  }
  
  #menu {
    background-color: #4682b4;
    padding: 3px;
  }
  
  #menu ul {
    text-align: center;
    padding-left: 20%;
    list-style: none;
  }
  
  #menu ul li {
    display: inline;
  }
  
  #menu ul li a {
    color: #ffffff;
  
    /* padding-left: 5%; */
    margin: 50px;
    background-color: #4682b4;
    font-size: xx-large;
    text-decoration: none;
  }
  
  #menu ul li a:hover {
    background-color: #b0c4de;
  }
  
  #Promocoes {
    display: flex;
    flex-direction: row;
  }
  
  #Promocoes img {
    align-content: center;
    padding: 25px;
  }
  
  #item {
    text-align: center;
    border-radius: 10px;
    margin: 20px;
    background-color: rgba(9, 50, 99, 0.35);
  }
  
  #item p {
    font-size: 14px;
  }
  
  #item button {
    background-color: #ffffff;
    padding: 10px;
    border-radius: 5px;
    cursor: pointer;
    border: none;
    font-weight: bold;
  }
  #item button:hover {
    background-color: #b0c4de;
  }
  
  /* Sobre Nos */
  
  
  
  #historia {
    margin-left: 200px;
    margin-right: 200px;
    font-size: 20px;
  }
  
  #historia img {
    padding-left: 100px;
    align-self: center;
  }
  
  /* SORTEIO */
  
  .legenda ul li{
    list-style: none;
    
    display: inline-block;
    font-weight: bolder;
    margin-right: 1%;
    margin-top: 5px; 
    margin-bottom: 10px; 
  }
  
  .disponivel {
    cursor: default;
    background-color: #ffffff;
    border: 2px #a9a9a9 solid;
    border-radius: 5px;
    padding: 8px;
  
  }
  
  .reservados {
    cursor: not-allowed; 
    background-color: lightgreen;  
    border: 2px green solid;
    color: #ffffff;
    border-radius: 5px;
    padding: 8px;
  
  }
  
  .pagos {
    cursor: not-allowed; 
    background-color: lightsalmon;
    border: 2px indianred solid;
    color: #ffffff;
    border-radius: 5px;
    padding: 8px;
  
  }
  
  .enviar {
    background-color: #4682b4;
    cursor: pointer; 
    color: #ffffff;
    border: #4682b4 solid;
    border-radius: 5px;
    padding: 8px;
  
  }
  
  .lista_sorteio {
    margin-left: 200px;
    margin-right: 200px;
    font-size: 20px;
  }
  
  
  
  .lista ul li {
      display: inline;
  
  }
  
  .lista ul li a {
    display: block;
    border: 2px solid #bfc0bf;
    border-radius: 50%;
    width: 100%;
    line-height: 40px;
    max-width: 75px;
    height: auto;
    font-weight: 700;
    text-decoration: none;
    display: inline;
    box-sizing: border-box;
    padding: 20px;
    font-family: sans-serif;
    font-size: 13px;
    color: #ffffff;
    background-color:rgb(85, 161, 108);
    border-color: #212529;
    margin-right: 50px;
  }
  
  .btn {
      display: inline-block;
      font-weight: 400;
      color: #212529;
      text-align: center;
      vertical-align: middle;
      cursor: pointer;
      -webkit-user-select: none;
      user-select: none;
      background-color: transparent;
      border: 1px solid transparent;
      padding: .375rem .75rem;
      font-size: 1rem;
      line-height: 1.5;
      border-radius: .25rem;
      transition: color .15s ease-in-out,background-color .15s ease-in-out,border-color .15s ease-in-out,box-shadow .15s ease-in-out;
  
  }
  
  .lista ul li a:hover {
    color: #212529;
    background-color: #ffffff;
    font:bolder;
    transition: all 600ms ease;
  
  }
  
  .lista ul li a.active {
    background-color: #f90;
  }

<div class = "lista">
        <ul >
            <li>
                <a href = "#000" id = "000" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">001</a>        
            </li>
            <li>
                <a href = "#001" id = "001" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">002</a>        
            </li>
            <li>
                <a href = "#002" id = "002" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">003</a>        
            </li>
            <li>
                <a href = "#003" id = "003" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">004</a>        
            </li>
            <li>
                <a href = "#004" id = "004" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">005</a>        
            </li>
            <li>
                <a href = "#005" id = "005" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">006</a>        
            </li>
            <li>
                <a href = "#006" id = "006" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">007</a>        
            </li>
            <li>
                <a href = "#007" id = "007" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">008</a>        
            </li>
            <li>
                <a href = "#008" id = "008" class = "btn_reservas" data-original-title = "Número 001 Pago por: Pedro">009</a>        
            </li>
        </ul>
    </div> 
</div>

<hr>

<p>Get the sum of the numbers in the array.</p>

<p id = "demo"></p>

<hr>

</body>
</html>