This is the code from Monads - episode #21 of FunFunFunction (https://www.youtube.com/playlist?list=PL0zVEGEvSaeFSwPn06GKArptSxiP1Gff8)

monad-stream-example.js

const fetch = require('node-fetch')
const Bacon = require('baconjs')

function getInPortuguese(word) {
  // Google Translate API is a paid (but dirt cheap) service. This is my key
  // and will be disabled by the time the video is out. To generate your own,
  // go here: https://cloud.google.com/translate/v2/getting_started
  const apiKey =
    'AIzaSyB4DyRHIsNhogQXmH16YKbZfR-lTXrQpq0'
	const url =
    'https://www.googleapis.com' +
    '/language/translate/v2' +
  	'?key=' + apiKey +
    '&source=en' +
    '&target=pt' +
    '&q=' + encodeURIComponent(word)
  const promise = fetch(url)
 		.then(response => response.json())
	  .then(parsedResponse =>
    	parsedResponse
      	.data
        .translations[0]
        .translatedText
    )
  const stream = Bacon.fromPromise(promise)
  return stream
}

const stream = new Bacon.Bus()

stream
  .flatMap(word => getInPortuguese(word))
  .map(word => word.toUpperCase())
  .onValue(word => console.log(word))

stream.push('cat')
stream.push('meal')
stream.push('trumpet')

// Output of running this file will be:
// TROMBETA
// REFEIÇÃO
// GATO

@ahlusar1989, how about this?

https://babeljs.io/repl/#?evaluate=true&presets=es2015%2Creact%2Cstage-2&code=const%20fetch%20%3D%20require('node-fetch')%0Aconst%20Bacon%20%3D%20require('baconjs')%0A%0Afunction%20getInPortuguese(word)%20%7B%0A%20%20%2F%2F%20Google%20Translate%20API%20is%20a%20paid%20(but%20dirt%20cheap)%20service.%20This%20is%20my%20key%0A%20%20%2F%2F%20and%20will%20be%20disabled%20by%20the%20time%20the%20video%20is%20out.%20To%20generate%20your%20own%2C%0A%20%20%2F%2F%20go%20here%3A%20https%3A%2F%2Fcloud.google.com%2Ftranslate%2Fv2%2Fgetting_started%0A%20%20const%20apiKey%20%3D%0A%20%20%20%20'AIzaSyB4DyRHIsNhogQXmH16YKbZfR-lTXrQpq0'%0A%09const%20url%20%3D%0A%20%20%20%20'https%3A%2F%2Fwww.googleapis.com'%20%2B%0A%20%20%20%20'%2Flanguage%2Ftranslate%2Fv2'%20%2B%0A%20%20%09'%3Fkey%3D'%20%2B%20apiKey%20%2B%0A%20%20%20%20'%26source%3Den'%20%2B%0A%20%20%20%20'%26target%3Dpt'%20%2B%0A%20%20%20%20'%26q%3D'%20%2B%20encodeURIComponent(word)%0A%20%20const%20promise%20%3D%20fetch(url)%0A%20%09%09.then(response%20%3D%3E%20response.json())%0A%09%20%20.then(parsedResponse%20%3D%3E%0A%20%20%20%20%09parsedResponse%0A%20%20%20%20%20%20%09.data%0A%20%20%20%20%20%20%20%20.translations%5B0%5D%0A%20%20%20%20%20%20%20%20.translatedText%0A%20%20%20%20)%0A%20%20const%20stream%20%3D%20Bacon.fromPromise(promise)%0A%20%20return%20stream%0A%7D%0A%0Aconst%20stream%20%3D%20new%20Bacon.Bus()%0A%0Astream%0A%20%20.flatMap(word%20%3D%3E%20getInPortuguese(word))%0A%20%20.map(word%20%3D%3E%20word.toUpperCase())%0A%20%20.onValue(word%20%3D%3E%20console.log(word))%0A%0Astream.push('cat')%0Astream.push('meal')%0Astream.push('trumpet')%0A%0A%2F%2F%20Output%20of%20running%20this%20file%20will%20be%3A%0A%2F%2F%20TROMBETA%0A%2F%2F%20REFEI%C3%87%C3%83O%0A%2F%2F%20GATO

@ahlusar1989 yes, chain is another word often used for the flatMap operation. In Haskell it's called bind. Many different names for the same thing.

Why don't you use simply

...
stream
  .flatMap(getInPortuguese)
  .map(word => word.toUpperCase())
  .onValue(console.log)
...

?

@Em-Ant Why not use this ? :)

...
stream
  .flatMap(getInPortuguese)
  .map(String.prototype.toUpperCase.apply)
  .onValue(console.log)
...

For learning purpose, I am using this code, without the need of setting up Google Translate API 😉

const portuguese = ['que', 'bonito', 'rir', 'pequeno', 'longe'];
const randomWord = arr => arr[Math.floor(Math.random() * (arr.length - 1))];
const getPortuguese = word => {
    const promise = Promise.resolve(`${word} ${randomWord(portuguese)}`);
    const stream = Bacon.fromPromise(promise);
    return stream;
};

Output using map():

Bacon.fromPromise({})
Bacon.fromPromise({})
Bacon.fromPromise({})

Output using flatMap():

CAT RIR
MEAL QUE
TRUMPET BONITO

FunFunFunction!