webpack.config.js

const path = require('path');

module.exports = {
    mode: 'development',
    entry: './src/index.ts',
    output: {
        filename: 'bundle.js',
        path: path.resolve(__dirname, 'dist')
    },
    resolve: {
        extensions: ['.tsx', '.ts', '.js']
    },
    devServer: {
        contentBase: path.join(__dirname, 'dist'),
        open: true,
        port: 9000
    },
    module: {
        rules: [{
                test: /\.(scss)$/,
                use: [{
                        // Adds CSS to the DOM by injecting a `<style>` tag
                        loader: 'style-loader'
                    },
                    {
                        // Interprets `@import` and `url()` like `import/require()` and will resolve them
                        loader: 'css-loader'
                    },
                    {
                        // Loader for webpack to process CSS with PostCSS
                        loader: 'postcss-loader',
                        options: {
                            plugins: function() {
                                return [
                                    require('autoprefixer')
                                ];
                            }
                        }
                    },
                    {
                        // Loads a SASS/SCSS file and compiles it to CSS
                        loader: 'sass-loader'
                    }
                ]
            },
            {
                test: /\.tsx?$/,
                use: 'ts-loader',
                exclude: /node_modules/
            }
        ]

    }
};