Example of util.promisify

promisify.js

// @see http://2ality.com/2017/05/util-promisify.html

const { promisify } = require('util');

const fs = require('fs');
const readFileAsync = promisify(fs.readFile);

const filePath = process.argv[2];

readFileAsync(filePath, { encoding: 'utf8' })
  .then((text) => {
      console.log('CONTENT:', text);
  })
  .catch((err) => {
      console.log('ERROR:', err);
  });