Solving Juggling Async problem from learnyounode with ES6 Promise

juggling-async-promise.js

var http = require('http')
  , bl = require('bl')
  , urls = process.argv.slice(2)

function httpGet(url) {
  return new Promise(function (resolve, reject) {
    http.get(url, function (response) {
      response.pipe(bl(function (err, data) {
        if (err) reject(err)
        resolve(data.toString())
      }))
    }).on('error', function (e) {
      reject(e)
    })
  })
}

// print results after all urls were loaded
Promise.all(urls.map(httpGet)).then(function (dataList) {
  dataList.forEach(function (data) {
    console.log(data)
  })
}).catch(console.error)

// another way, print first result ASAP
urls.map(httpGet).reduce(function (sequence, urlPromise) {
  return sequence.then(function () {
    // wait for loading complete...
    return urlPromise
  }).then(function (data) {
    console.log(data)
  })
}, Promise.resolve())