webpack.config.js

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

module.exports = {
    mode: "development",
    entry: {
        app: ['./src/index.tsx', 'webpack-hot-middleware/client'],
        vendor: ['react', 'react-dom']
    },
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'js/[name].bundle.js'
    },
    devtool: 'source-map',
    resolve: {
        extensions: ['.js', '.jsx', '.json', '.ts', '.tsx']
    },
    module: {
        rules: [
            { test: /\.(ts|tsx)$/, loader: 'ts-loader' },
            { enforce: "pre", test: /\.js$/, loader: "source-map-loader" },
            {
                test: /\.scss$/,
                  use: [{
                    loader: "style-loader"
                  }, {
                    loader: "css-loader" 
                  }, {
                    loader: "sass-loader"
                  }]
              }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({ template: path.resolve(__dirname, 'src', 'index.html') }),
        new webpack.HotModuleReplacementPlugin()
    ]
}