Creating Unsettled Promises

unsettledPromise.js

var fs = require('fs');

function readFile(filename) {
  return new Promise(function(resolve, reject) {
    fs.readFile(filename, {encoding: 'utf8'}, function(err, data) {
      if (err) {
        reject(err);
        return;
      }
      resolve(data);
    });
  });
}

var promise = readFile('hello.txt');

promise.then(function(data) {
  console.log('success: ' + data);
}, function(err) {
  console.log('fail: ' + err.message);
});