Asynchronous version of Node.js readFile.

readFileAsync.js

// make Promise version of fs.readFile() - enc is the encoding (i.e. utf-8)
fs.readFileAsync = function (filename, enc) {
  return new Promise(function (resolve, reject) {
    fs.readFile(filename, enc, function (err, data) {
      if (err) reject(err);
      else resolve(data);
    });
  });
};