Buffered RXJS

index.js

const { rxObserver } = require('api/v0.3');
const { interval, from, timer, of } = require('rxjs');
const { take, bufferCount, concatMap, delay, first, mergeMap, map, throttleTime, ignoreElements, startWith } = require('rxjs/operators');

const spaceTime = time => concatMap(value =>
    of(value).pipe(
    	delay(time)
    )
);

interval(10).pipe(
  take(10),
  bufferCount(3),
  mergeMap(counts => {
    const chars = counts.map(num => String.fromCharCode(65 + num));
    return from(chars);
  }),
  spaceTime(5),
).subscribe(rxObserver());