TypeError: (0 , _Ripple2.default) is not a function

[AltitudeTech]

this is the content of next.config.js

const withCSS = require("@zeit/next-css");
const internalReactToolboxDeps = /react-toolbox(?!.*node_modules)/;
const externalReactToolboxDeps = /node_modules(?!/react-toolbox(?!.*node_modules))/;

module.exports = withCSS({
cssModules: true,
cssLoaderOptions: {
importLoaders: 1,
localIdentName: "[local]__[hash:base64:5]"
},

webpack: (config, { dev, defaultLoaders }) => {
const { externals = [] } = config;
config.resolve.symlinks = false;
config.externals = externals.map(external => {
if (typeof external !== "function") return external;
return (ctx, req, cb) =>
internalReactToolboxDeps.test(req) ? cb() : external(ctx, req, cb);
});
config.module.rules.push({
test: /.jsx?$/,
loader: defaultLoaders.babel,
include: [internalReactToolboxDeps]
});

return config;

},
webpackDevMiddleware: config => {
const ignored = [config.watchOptions.ignored[0], externalReactToolboxDeps];
config.watchOptions.ignored = ignored;
return config;
}
});