ES7.js

'use strict'
// babel countfiles_es7.js -o countfiles_es7.out.js --optional runtime --source-maps inline

require('source-map-support').install();

import Promise from 'bluebird';
import path from 'path';

let fs = Promise.promisifyAll(require('fs'));

class FileCounter {
	static async countFiles(dir) {
		let files = await fs.readdirAsync(dir);
		let paths = files.map(file => path.join(dir, file));
		let stats = await* paths.map(path => fs.statAsync(path));
		return stats.filter(stat => stat.isFile()).length;
	}
}

(async function () {
	try {
		let num = await FileCounter.countFiles(__dirname);
		console.log('There are ' + num + ' files in ' + __dirname);
	} catch (err) {
		console.error(err);
	}
})();