transpile-esnext-modules.js

const MODULE_DIR = /(.*([\/\\]node_modules|\.\.)[\/\\](@[^\/\\]+[\/\\])?[^\/\\]+)([\/\\].*)?$/g;

{
	loader: 'babel-loader',
	test: /\.jsx?$/,
	include(filepath) {
		if (filepath.split(/[/\\]/).indexOf('node_modules')===-1) return true;
		let pkg, manifest = path.resolve(filepath.replace(MODULE_DIR, '$1'), 'package.json');
		try { pkg = JSON.parse(fs.readFileSync(manifest)); } catch (e) {}
		return !!(pkg.module || pkg['jsnext:main']);
	}
}

Line 10 should be pkg.module.

return !!pkg && !!(pkg.module || pkg['jsnext:main']);

Thanks.
Don't forget to import fs (const fs = require('fs');)