esm

index.mjs

'use strict';
// node --experimental-modules index.mjs

import fs from 'fs';

import util from 'util';

const readFile = util.promisify(fs.readFile);

const fnThen = (result) => {
  console.log('result', result.toString());
}

const fnCatch = (error) => {
  console.log('error', error);
}

readFile('./package.json')
  .then(fnThen)
  .catch(fnCatch);