Hot reloading is a term used in the JavaScript world, which is used to refer to live changes in the browser without the browser being refreshed. In the React ecosystem, React Hot Loader is widely used for the same purpose.
React Hot Loader is a plugin for Webpack, which results in instantaneous and live changes in the browser, without losing states. The changes can be visible while editing React components and functions as LiveReload
for React.
Some limitations of the react hot loader first version have been discussed by the author (Dan Abramov) here at https://medium.com/@dan_abramov/the-death-of-react-hot-loader-765fa791d7c4#.fc78lady9. The details of the project can be found at https://gaearon.github.io/react-hot-loader/.