webpack.config.js

const path = require('path');
const webpack = require('webpack');

const rules = [
  {
    test: /\.(js|jsx|ts|tsx)$/,
    exclude: /(node_modules)/,
    loader: 'babel-loader',
    options: { presets: ['@babel/env'] },
  },
  {
    test: /\.css$/,
    use: ['style-loader', 'css-loader'],
  },
  {
    test: /\.js$/,
    exclude: /(node_modules\/react-leaflet-heatmap-layer-v3)/,
    enforce: 'pre',
    use: ['source-map-loader'],
  },
  {
    test: /.(png|svg|jpe?g|gif|woff2?|ttf|eot)$/,
    use: ['file-loader'],
  },
];

// TODO - move this config to a dedicated environment file.
// TODO - use process.env.NODE_ENV which will directly return the environment string "development", "production".
module.exports = (env) => {
  const production = env.production;
  return {
    entry: './src/index.tsx',
    mode: production ? 'production' : 'development',
    devtool: production ? undefined : 'source-map',
    module: {
      rules: rules,
    },
    resolve: { 
      extensions: ['*', '.js', '.jsx', '.ts', '.tsx'],
      fallback: {"fs": false}
    },
    output: {
      filename: 'bundle.js',
    },
    devServer: {
      port: 3000,
      hot: true,
    },
    plugins: production ? [] : [new webpack.HotModuleReplacementPlugin()],
    ignoreWarnings: [/Failed to parse source map/],
  };
};