Shopify Add to cart jQuery

gistfile1.txt

  // ==========Add to cart jquery==========//
 document.addEventListener('DOMContentLoaded', function() {
  document.querySelectorAll('.productAddtocartButton').forEach(function(button) {
    button.addEventListener('click', function(e) {
      var btnText = button.querySelector('.btn-text').innerText;
      e.preventDefault(); var thisAvailable = this.getAttribute('data-available'); 
      var variantId = this.getAttribute('variant-id');
      var quantity = 1; button.querySelector('.btn-text').textContent = 'Loading...'; 
      if (thisAvailable == 'true'){
      fetch('/cart/add.js', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          id: variantId,
          quantity: quantity,
          properties: {
          'Product Size': 'Full'
          }
        }),
      })
      .then(response => response.json())
      .then(data => {
       button.querySelector('.btn-text').textContent = btnText; 
         console.log('data :', data); 
         Spruce.store('drawer').productOpen = true;
        document.body.dispatchEvent(new CustomEvent('label:modalcart:afteradditem')); 
      })
      .catch((error) => {
        button.querySelector('.btn-text').textContent = btnText; 
        console.error('Error:', error); 
      });
    } else{
        button.querySelector('.btn-text').textContent = 'Sold Out'; 
        setTimeout(function() { 
        button.querySelector('.btn-text').textContent = btnText;  
        }, 3000);
    }
    });
  }); 
});