import * as express from 'express'; import * as webpack from 'webpack'; import * as webpackDevMiddleware from 'webpack-dev-middleware'; const compiler = webpack({}); let webpackDevMiddlewareInstance = webpackDevMiddleware(compiler); webpackDevMiddlewareInstance = webpackDevMiddleware(compiler, { noInfo: false, quiet: false, lazy: true, watchOptions: { aggregateTimeout: 300, poll: true, }, publicPath: '/assets/', index: 'index.html', headers: { 'X-Custom-Header': 'yes' }, stats: { colors: true, }, reporter: null, serverSideRender: false, }); const app = express(); app.use([webpackDevMiddlewareInstance]); webpackDevMiddlewareInstance.close(); webpackDevMiddlewareInstance.invalidate(); webpackDevMiddlewareInstance.waitUntilValid(() => { console.log('Package is in a valid state'); });