RxJS sequence equivalent to promise.then()?

Question

I used to develop a lot with promise and now I am moving to RxJS. The doc of RxJS doesn\'t provide a very clear example on how to move from promise chain to observer sequenc

Answer 1

A more modern alternative:

import {from as fromPromise} from 'rxjs';
import {catchError, flatMap} from 'rxjs/operators';

fromPromise(...).pipe(
   flatMap(result => {
       // do something
   }),
   flatMap(result => {
       // do something
   }),
   flatMap(result => {
       // do something
   }),
   catchError(error => {
       // handle error
   })
)

Also note that for all this to work, you need to subscribe to this piped Observable somewhere, but I assume it's handled in some other part of the application.