module.exports = { webpack: function (config, env) { return config; }, devServer: function (configFunction) { // Return the replacement function for create-react-app to use to generate the Webpack // Development Server config. "configFunction" is the function that would normally have // been used to generate the Webpack Development server config - you can use it to create // a starting configuration to then modify instead of having to create a config from scratch. return function (proxy, allowedHost) { // Create the default config by calling configFunction with the proxy/allowedHost parameters const config = configFunction(proxy, allowedHost); config.proxy = { "/socket.io": { target: "http://localhost:3001", ws: true } } // Return your customised Webpack Development Server config. return config; }; } }