This PR addresses an issue where trying to load the same FITS file twice or a non-FITS file as a FITS file would cause the web client to freeze. Now loading the same FITS file twice will work as expected and trying to load a non-FITS file will result in a warning being show to the user. There has been some discussion with @pkgw about alternatives to using the JavaScript alert in the backend, but implementing that is beyond the scope of this PR.
This PR addresses an issue where trying to load the same FITS file twice or a non-FITS file as a FITS file would cause the web client to freeze. Now loading the same FITS file twice will work as expected and trying to load a non-FITS file will result in a warning being show to the user. There has been some discussion with @pkgw about alternatives to using the JavaScript alert in the backend, but implementing that is beyond the scope of this PR.