listenForModal.jsx

// crude first implementation for proof
document.addEventListener('DOMContentLoaded', () => {

  // Select the node that will be observed for mutations
  const targetNode = document.getElementById('modal-holder');

  // Options for the observer (which mutations to observe)
  const config = { attributes: true, childList: true, subtree: true };

  // Callback function to execute when mutations are observed
  const callback = function(mutationsList, observer) {
      for(let mutation of mutationsList) {
          if (mutation.type === 'childList') {
              console.log('A child node has been added or removed.');
          }
          else if (mutation.type === 'attributes') {
              console.log('The ' + mutation.attributeName + ' attribute was modified.');
          }
      }
  };

  // Create an observer instance linked to the callback function
  const observer = new MutationObserver(callback);

  // Start observing the target node for configured mutations
  observer.observe(targetNode, config);
})