For personal projects I just use plain javaScript, ES5 even, without any compile steps, everything loads instantly and runs on every browser that supports JavaS

For personal projects I just use plain javaScript, ES5 even, without any compile steps, everything loads instantly and runs on every browser that supports JavaScript, and the development can be set up in any environment/OS without headaches. I do use minification for production but that is not really necessary if the browser supports loading JS-script tags async (all major browsers). The bundle gets very small without any frameworks attached. Debugging is easy with the browser built in dev-tools - with small error messages that always have the correct line (eg. no source maps). I'm currently working on a 100,000+ line JS project that uses the plugin pattern with script tags and it's very manageable, adding new features is fast and fun. There are of course trade-offs, I can't just "npm install react-x-y-z", but the browser API's are extensive, you can do just about anything on the front-end with just the native browser components and API's.