You will need to install a user script manager extension to install this script.
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive
// @require https://greasyfork.org/scripts/408787-js-toast/code/js-toast.js?version=837479
Original author did not publish the script to any supported CDN, so the script is uploaded here.
Original un-minified code is ES6 module that is unsupported by Greasy Fork, so I had to copy the original minified code instead.