read_files_promises.js

var fs = require('fs');

var files = ['foo.txt', 'bar.txt', 'baz.txt'];

var promises = [];

for (var i = 0; i < files.length; i++) {
    promises.push(readFile(files[i]));
}

Promise.all(promises).then(function(results) {
    // results - array with 3 text elements.
    console.log('results', results);
}).catch(function(error) {
    console.log('error', error);
});

function readFile(name) {
    return new Promise(function(resolve, reject) {
        var result = '';
        var stream = fs.createReadStream(name, {encoding: 'utf8'}).on(
            'readable',
            function(s) {
                var buf;
                while ((buf = stream.read()) !== null) {
                    result += buf;
                }
            }
        ).once('end', function() {
            resolve(result);
        }).once('error', function(error) {
            reject(error);
        });
    });
}

Очень изящно. Благодарствую!

Promise is not defined