Load scripts asynchronously and run callback functions (Swiper example)

async-scripts-loading.js

const loadScript = (FILE_URL, async = true, type = 'text/javascript') => {
  return new Promise((resolve, reject) => {
    try {
      const scriptEle = document.createElement('script');
      scriptEle.type = type;
      scriptEle.async = async;
      scriptEle.src = FILE_URL;

      scriptEle.addEventListener('load', (ev) => {
        resolve({
          status: true
        });
      });

      scriptEle.addEventListener('error', (ev) => {
        reject({
          status: false,
          message: `Failed to load the script ${FILE_URL}`
        });
      });

      document.body.appendChild(scriptEle);
    } catch (error) {
      reject(error);
    }
  });
};

function initSwipers() {
  let productItemsImages = document.querySelectorAll('.ProductItem__Swiper');
  console.log(productItemsImages);
  if (productItemsImages) {
    productItemsImages.forEach(el => {
      const swiper = new Swiper(el, {
        
      })
    })
  }  
}

if (window.Swiper) {
  initSwipers();
} else {
  loadScript('https://unpkg.com/swiper@8/swiper-bundle.min.js')
  .then( data  => {
    console.log('Swiper loaded successfully', data);
    initSwipers();
  })
  .catch( err => {
    console.error(err);
  });
}