In this package you'll find two categories of things:
Observables (regular and specialised ones)
operators (functions that'll wrap the observable into an observable with additional mechanics)
npm i @hullo/core
...then in your code:
import { Observable, map } from '@hullo/core'​new Observable(observer => {observer.next(1).then(() => observer.next(2)).then(() => observer.next(3));.then(() => observer.complete());}).pipe(map(n => n * 2)).subscribe({next: v => { console.log(v) }});​// logs out 2,4 and 6
​