index.js

const { rxObserver, palette } = require('api/v0.3');
const { iif,pipe,of,merge, timer, from, once } = require('rxjs');
const { switchMapTo,mapTo,filter,windowWhen,delay,mergeMap,map,switchMap, concatMap, take, zip, ignoreElements, startWith } = require('rxjs/operators');

// stream for coloring
const palette$ = from(palette);

const callStt = pipe(
    filter(i=>i%3==2),
    map(i=> Marble(i+">", i.color)),
    delay(5)
)

const callChatbot = (data) =>
  new Promise(resolve =>
    setTimeout(() =>
      resolve(Marble(data+"@", data.color)),
      10));
      
const callTts = pipe(
  mergeMap(v => timer(0, 15).pipe(
    take(3),
    map(v2=> Marble(v+"#"+v2, v.color)),
    ))
)

function call(s) {
  s.subscribe(rxObserver('voicebot request'))
  s
  .pipe(
    pipeIf(v => v.valueOf() === 'I', pipe, callStt),
    mergeMap(callChatbot),
    callTts
  )
  .subscribe(rxObserver('voicebot response (>: STT, @: Chatbot, #: TTS)'))
}

// helpers
// creates a colored Marble
function Marble(value,color) {
  return {
    valueOf: ()=>value
    , color
  };
}

function pipeIf(predicate, a, b=pipe) {
  return function (source) {
    return source.pipe(
      mergeMap(value => predicate(value) ?
      of(value).pipe(a) :
      of(value).pipe(b))
    )
  }
}

function colorize(color) {
  return pipe(
    map(y => Marble(y, color))
  );
}


const source1$ = merge(
    of('I'),
    timer(5, 20).pipe(take(10))
  ).pipe(
    zip(from(palette), Marble)
  );  
  call(source1$)

const source2$ = merge(
    of('I'),
  ).pipe(
    zip(from(palette), Marble)
  );  
  call(source2$)