HMR
HMR (Hot Module Replacement) allows you to apply changes without restarting a plugin.
Note: A plugin should be running to get HMR working.
To enable HMR the following steps are needed:
- Create 
webpack.ui.config.jsfile and add the following code: 
var configure = require('react-figma-webpack-config/hmr');
module.exports = configure();
- Create 
ui.htmlfile add the following code: 
<script type="text/javascript" src="http://localhost:8080/ui.js"></script>
- Change starting script at 
package.json: 
-"webpack:watch": "webpack --watch"
+"webpack:watch": "webpack && webpack-dev-server --config webpack.ui.config.js"
- Add the following code to React entry point file (it's 
src/ui.tsxusually): 
...
// @ts-ignore
if (module.hot) {
    // @ts-ignore
    module.hot.accept();
}
See full example here.