Setting up Webpack 4

1. Install all the necessary dependencies

npm i @babel/core @babel/preset-env @babel/preset-react babel-loader webpack@4 webpack-cli

2. Set-up webpack config file (webpack.config.js)

const path = require('path');

module.exports = {
    entry: './src/index.js',
    output: {
        filename: 'bundle.js',
        path: path.resolve(__dirname, 'public')
    },
    module: {
        rules: [{ 
            test: /\.jsx?$/, 
            exclude: /node_modules/, 
            loader: "babel-loader" 
        }]
    }
}

3. Set-up babel config (.babelrc)

{
    "presets": [ "@babel/preset-env", "@babel/preset-react" ]
}

4. Set build script in package.json

"scripts": {
    "build": "webpack -d --watch"
}