callback-with-promise

index.js

const fs = require('fs')

function readPackage (callback) {
  //as of now we do not have default values in Node.js
  callback = callback || function () {}
  return new Promise((resolve, reject) => {
    fs.readFile('./package.json', (err, data) => {
      if (err) {
        reject(err)
        return callback(err)
      }
      resolve(data)
      return callback(null, data)
    })
  })
}

module.exports.readPackage = readPackage