webpack.config.js

const path = require('path');

module.exports = (env, options) => {
	// Common Configurations for multiple outputs
	var commonConfig = {
		// If webpack is used under development mode,
		// generate source maps for better debugging experience
		devtool: options.mode === 'development' ? 'inline-source-map' : false,
		entry: {
			"d3-mitch-tree": './src/index.js'
		},
		module: {
			rules: [{
				test: /\.js$/,
				exclude: /(node_modules|bower_components)/,
				use: {
					loader: 'babel-loader',
					options: {
						presets: ['@babel/preset-env']
					}
				}
			}]
		}
	};

	var fullConfig = {
		...commonConfig, // ES6 Spread operator
		output: {
			filename: '[name].js',
			path: path.resolve(__dirname, 'dist/js'),
			library: ["d3", "mitchTree"],
			libraryExport: 'default',
			libraryTarget: 'umd',
			publicPath: './dist',
			umdNamedDefine: true,
			// To make it compatible with both web and node for UMD bundles,
			// as well as fix an issue with webpack:
			//   https://github.com/webpack/webpack/issues/6677
			//   https://github.com/webpack/webpack/issues/6525
			globalObject: "this"
		},
		optimization: {
			minimize: false
		}
	}

	var minifiedConfig = {
		...commonConfig,
		output: {
			filename: '[name].min.js',
			path: path.resolve(__dirname, 'dist/js'),
			library: ["d3", "mitchTree"],
			libraryExport: 'default',
			libraryTarget: 'umd',
			publicPath: './dist',
			umdNamedDefine: true,
			globalObject: "this"
		},
		optimization: {
			minimize: true
		}
	};

	var entryPointConfig = {
		...commonConfig,
		target: 'node',
		output: {
			filename: '[name].js',
			path: path.resolve(__dirname, 'lib'),
			library: ["d3", "mitchTree"],
			libraryExport: 'default',
			libraryTarget: 'umd',
			umdNamedDefine: true
		},
		optimization: {
			minimize: true
		}
	}

	return [
		fullConfig, minifiedConfig, entryPointConfig
	];
};