Order of invocation of Multiple Finalize callbacks

[Vikasg7]

Bug Report

Current Behavior
Callbacks registered with finalizing operator are called in flipped order.

Reproduction
Link to codepen

const problem1 = pipe(
  from([1,2,3]),
  finalize(() => log("1")),
  map(x => x * 2),
  finalize(() => log("2"))
)

problem1.subscribe()

Current output

"2"
"1"

Expected output
This is what I expect. I would like to finalize previous things first before the things further down my chain.

"1"
"2"

Environment

• Runtime: Node v9.4.0, Chrome v68.0.3440.106
• RxJS version: 5+, 6+

[cartant]

The order in which the finalize operators are called depends upon several factors.

In your snippet, they are called in 'reverse' order because the source and the composed operators complete synchronously.

In this example, they are not called in reverse order because the source observable completes before the observable within the mergeMap:

import { asyncScheduler, from, of } from "rxjs";
import { finalize, mergeMap } from "rxjs/operators";

const problem1 = from([1,2,3]).pipe(
  finalize(() => console.log("1")),
  mergeMap(x => of(x * 2, asyncScheduler)),
  finalize(() => console.log("2"))
);
problem1.subscribe();

Essentially, this behaviour is be design.