const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  mode: 'development',
  entry: './src/index.js',
  output: {
    filename: 'bundle.js',
    path: path.join(__dirname, 'public'),
  },

  module: {
    rules: [
      {
        use: {
          loader: 'babel-loader',
          options: {
            presets: [
              '@babel/preset-env',
              '@babel/preset-react',
              { plugins: ['@babel/plugin-proposal-class-properties'] },
            ],
          },
        },
        test: /\.js$/,
        exclude: /node_modules/,
      },
    ],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: 'src/index.html',
    }),
  ],
};

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  mode: 'development',
  entry: './src/index.js',
  output: {
    filename: 'bundle.js',
    path: path.join(__dirname, 'public'),
  },

  module: {
    rules: [
      {
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env', '@babel/preset-react'],
          },
        },
        test: /\.js$/,
        exclude: /node_modules/,
      },
    ],
  },

  plugins: [
    new HtmlWebpackPlugin({
      template: 'src/index.html',
    }),
  ],
};

--- 
+++ 
@@ -15,7 +15,11 @@
         use: {
           loader: 'babel-loader',
           options: {
-            presets: ['@babel/preset-env', '@babel/preset-react'],
+            presets: [
+              '@babel/preset-env',
+              '@babel/preset-react',
+              { plugins: ['@babel/plugin-proposal-class-properties'] },
+            ],
           },
         },
         test: /\.js$/,
@@ -23,7 +27,6 @@
       },
     ],
   },
-
   plugins: [
     new HtmlWebpackPlugin({
       template: 'src/index.html',
Set `@babel/plugin-proposal-class-properties` as option in webpack

Fixes webpack build error due to class properties
https://stackoverflow.com/a/52693007/452233
