To trace the functionality of the 'Login' button with data-testid 'top-nav-login-button', open Chrome Developer Tools, select the Elements tab, and use the search function (Ctrl+F) to find the element.
To fix, you'll want to wait for the image itself to load before initializing CropperJS. Something like: const img = document.getElementById('editorImage'); img.onload = () => { new Cropper(img, { /* options */ }); };