forcing webpackdev server to write files

config/webpack.config.flask.js

@@ -12,6 +12,7 @@ const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
 const SWPrecacheWebpackPlugin = require('sw-precache-webpack-plugin');
 const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
 const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
+const WriteFilePlugin = require('write-file-webpack-plugin');
 const getClientEnvironment = require('./env');
 const paths = require('./paths');
 // Webpack uses `publicPath` to determine where the app is being served from.
@@ -253,7 +254,8 @@ module.exports = {
       new ManifestPlugin({
         fileName: 'asset-manifest.json',
       }),
-      new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/)
+      new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
+      new WriteFilePlugin()
     ],
     // Some libraries import Node modules but don't use them in the browser.
     // Tell Webpack to provide empty mocks for them so importing them works.