import config from '../../../data/__config.json';
var selectedThemeModule = './themes/'+config.currentTheme+'/boot.js';
const Theme = require(selectedThemeModule);
export default Theme.default;

import config from '../../../data/__config.json';

const theme = require(`./themes/${config.currentTheme}/boot.js`);

export default theme.default;

Simplify syntax and use ES6 features