StealJs
(wich also has good building/bundling capabilities). The example and demo of hot-reloading you can find here: https://github.com/whitecolor/can-hot
reactjs
hot-reloading works fine with https://github.com/tyscorp/react-transform-jspm-hmr works for it as well
if (location.origin.match(/localhost/)) {
System.trace = true
System.import('capaj/systemjs-hot-reloader').then(function(HotReloader){
new HotReloader.default('//localhost:3000') // chokidar-socket-emitter port
})
}