webpack.config.js

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

module.exports = {
    entry: './client/index.js',
    output: {
        path: path.join(__dirname, '/dist'),
        filename: 'bundle.js',
    },
    plugins: [
        new HTMLWebpackPlugin({
            template: './client/index.html',
        }),
    ],
    mode: process.env.NODE_ENV,
    module: {
        rules: [
            {
                test: /\.jsx?/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['@babel/preset-env', '@babel/preset-react'],
                    },
                },
            },
            {
                test: /\.css$/i,
                include: path.resolve(__dirname, 'client'),
                use: ['style-loader', 'css-loader', 'postcss-loader'],
            },
        ],
    },
    devServer: {
        static: [path.join(__dirname, 'client')],

        // proxy setting to be included
        proxy: {
            '/api': {
                target: 'http://localhost:3000',
                secure: false,
            },
             '/login': {
                target: 'http://localhost:3000',
                secure: false,
            },
              '/history': {
                target: 'http://localhost:3000',
                secure: false,
            },
        },
        // fallback to root for other urls
        historyApiFallback: true,
        // added headers into devServer
        headers: {
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
            "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
        }
    },
    resolve: {
        // Enable importing JS / JSX files without specifying their extension
        extensions: ['.js', '.jsx'],
    },
};

// possible way to get CORS to work, adding it to dev server.
// devServer: {
//     ...
//     headers: {
//       "Access-Control-Allow-Origin": "*",
//       "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
//       "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
//     }
//   }