webpack.config.js

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

const BUILD_DIR = path.resolve(__dirname, 'public/js/build');
const APP_DIR = path.resolve(__dirname, 'public/js');

const config = {
    context: APP_DIR,
    entry: {
        app: './main.js'
    },
    output: {
        path: BUILD_DIR,
        filename: 'bundle.js',
        publicPath: "/"
    },
    module: {
        rules: [
            {
                test: /\.(js|jsx)$/, //Check for all js files
                exclude: /node_modules/,
                loader: 'babel-loader',
                options: {
                    babelrc: false,
                    presets: ['@babel/preset-env', '@babel/preset-react'],
                    // This is a feature of `babel-loader` for webpack (not Babel itself).
                    // It enables caching results in ./node_modules/.cache/babel-loader/
                    // directory for faster rebuilds.
                    cacheDirectory: true,
                    plugins: [ '@babel/plugin-proposal-function-bind', '@babel/plugin-proposal-class-properties'],
                },
            }
        ]
    },
    devServer: {
        contentBase: __dirname + '/public/js'
    },
    devtool: "eval-source-map"
};

module.exports = config;