n this lesson, we will set up Hot Module Reloading(HMR), making it possible to load new definitions for React components and MST models and apply them to a running application.

In this lesson you will learn:

• How HMR roughly works
• How to accept changes to components
• How to accept changes to changing model definitions, while keeping state

let wishList = WishList.create(initialState)function renderApp() {    ReactDOM.render(
       , document.getElementById("root"))}renderApp()if (module.hot) {    module.hot.accept(["./components/App"], () => {        // new components        renderApp()    })    module.hot.accept(["./models/WishList"], () => {        // new model definitions        const snapshot = getSnapshot(wishList)        wishList = WishList.create(snapshot)        renderApp()    })}