webpack.config.js

const path = require("path");
module.exports = {
  context: __dirname,
  entry: "./src/index.js",
  output: {
    path: path.resolve(__dirname, "dist"),
    filename: "index.js",
    publicPath: "/",
  },
  devServer: {
    historyApiFallback: true,
    allowedHosts: 'all',
    headers: {
      "Access-Control-Allow-Origin": "*",
      "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
      "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
    },
    client: {
      webSocketURL: {
        hostname: 'localhost'
      },
    }
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        use: "babel-loader",
      },
      {
        test: /\.(s(a|c)ss)$/,
        use: ['style-loader','css-loader', 'sass-loader']
      },
      {
        test: /\.(png|j?g|svg|gif)?$/,
        use: "file-loader",
      },
    ],
  }
};